Chevy Casting Number identification - Block casting numbers

double check your block castings #s.

IMHO, DON'T use the 1103 cam with the 1.72 valves. the 1103 will want to rev high, 5500 rpm+ in a 355. heads with 1.72 valves DON'T like to breath high. 355's with 1.72 valves come on quick, but give up quick too. they'll be done at 4200 rpm. so...... no need for a cam above 4200.

the 1102 is a good cam for a 9.25:1 355. very easy to hit 5200 with heads that have 1.94 intake valves. you might have to retard it for it to live. just depends what elevation you plan on running it at. a very good cam for a stock-mild 350. I like to use it in 350+ builds, 8.8:1-9.0:1, with 882 heads. works every time for DD, street, 4x4 work trucks that need to pull, and haul sh**.

the crane 260 is a good cam, but with the 110* LSA, its gonna create less vacuum, compared to the 1102, it'll make more low rpm torq, not enough to feel, and give up quicker then the 1102. will pull strong up to 5000 in a 9.25:1 355 with heads that have 1.94 intake valves. it'll need to be retarded more then the 1102 at 9.25:1

IMHO you're gonna need more than 4:10:1 gears for 38" tires, stock stall and a th350. I use to run 39.5" swampers with 4.56:1 gears, 4 speed tranny with granny gear, a well built 360, 010 4 bolt block, more CR, better heads, long tube headers, glass packs, and it needed 5.38:1 or more gears.

just my 2 cents, and that's about all it worth. good luck with your build, make the best of it:thumbup:. rick

 

Single pattern, no need to cruch a 1.5 inch exhaust valve with more cam duration when your intake is only 1.72

 

Here's Iskenderian's take on it......

"Tech Tip - 2003
Longer Exhaust Duration: Is this really necessary?

Most stock camshafts from American production V8, V6 and 4 cylinder engines manufactured today are ground with the longer exhaust lobe duration. Or, another way of looking at this is that they are ground with shorter intake durations! The former embraces the viewpoint that either the Exhaust Ports or Exhaust Pipe system is somewhat restrictive, and is in need of an assist. The latter suggests that the intake system is rather efficient and cam timing can be trimmed back a bit with out much sacrifice in power, in order to maximize throttle response and cruising efficiency.

Take your pick here. There is no absolutely correct viewpoint - because both are probably true! In a stock engine running at conservative RPM levels, for the sake of overall efficiency, fuel economy and a quiet smooth running engine, this staggering of intake and exhaust duration is quite common and appropriate.

However, High Performance is another thing entirely. Change one factor, let's say in this case, the exhaust system (installing headers and larger pipes) and you have just negated in most cases, the need for that longer exhaust lobe. Now couple this change with a different intake system and camshaft and you have really scrambled the equation. But, wait just a moment. Why is it that so many people (racers & cam grinders alike) insist on running a cam with longer exhaust duration regardless of what equipment is employed? The answer is "habit". Most of them have been somewhat successful in doing it their way and will probably never change unless virtually forced by circumstances to do so.

Before we go any further however let's review what it actually is we are trying to do with an engine when we attempt to make more power. Our best result comes when we are cognizant of the fact that an engine is basically an air pump. We pump it in and out (although in a different form) and we have problems when one side or the other is restricted. Balance or the equilibrium or flow should be our objective, unless of course we are not trying to make more horsepower!

Example #1 (Oval track racing) Here, I have often observed that the most experienced drivers are those who are most likely to run a single pattern (equal on intake and exhaust duration) cam. Why? Because such cams always, I repeat always make more torque! These veterans have a more educated foot and greater experience in feathering the throttle in the corners. They can therefore, utilize the benefit of added torque, in the lower to mid RPM range, to their advantage.

Their counterparts, the younger drivers on the circuit, generally are not as experienced and may at times actually get "crossed up" in the corners especially with a lighter car or when they are learning the ropes. In their case, a longer exhaust duration is often the more appropriate choice. It will often help them to drive better, more "flat footed" if you will, without consequence. But please for the sake of accuracy, let us be truthful. The benefit comes from an actual bleeding off of low to mid range torque, which is always what happens when Exh. Duration is lengthened, not from any improvement. The improvement, (if any) would come because of an improvement in scavenging at the extreme upper end of the power curve and would usually be marginal at best. Yet the so-called "extra power" potential of a longer Exh. Duration cam is most often why they are touted - power most people are backing away from at the end of the strait away!

Example #2 (Drag Racing) At the drag strip it's a little different and I feel more honest. Here, racers have long enjoyed longer exhaust and longer durations across the board (If I may add specifically for the purpose of "killing" low-end torque) to keep the tires from too easily breaking lose. This has been successful and sometimes actually results in a slight increase in top end power - something you can actually use in drag racing since it is a full throttle endeavor through the lights. Keep in mind here though, it's quite possible that a longer duration cam overall would have done just as well or better. In other words if you needed that longer exhaust for top end, perhaps the intake could have benefited from such a lengthening as well.

One of my favorite expressions is how "The Drag Racing mentality has infiltrated the ranks of Oval Track". Many have crossed over and made the switch in the past 10-15 years and some have brought their preconceived notions about how to cam an engine with them. A few may actually read these concepts and if they do so will at least come away with a better understanding of what they are doing. On the other hand they also could find that this information might actually help their cars to run just a bit faster!

Note: Readers may find Camfather Ed Iskenderian's Top Tuners Tip #33 "Can an Exhaust System Over-Scavenge the Combustion Chambers" to be a relevant precursor."

And here's my take on it......

A 38" tire with a 4.10 gear is the same as a 27" tire with a 2.91 gear. Nobody in his right mind would try to cam up a motor with a 2.91 gear in the rear. Crane Energizer 260-H10 is all the cam I'd use with that gear and I wouldn't use that much cam if the static compression ratio was a little lower. If the SCR was down around 8.75:1, I'd use the Crane H-248-2 (operating range 800-4600). As Rick said, the heads will be done by 4200 anyway, so lighten up on the cam so that you can make power from idle to 4500.

In running DynoSims, I have seen very little improvement between 1.5 and 1.6 rockers, maybe 10-12 hp. I wouldn't put the added stress of 1.6 rockers on the valvetrain for that little bit of gain. I think most everyone will agree that full roller rockers will free-up approximately 20 hp due to less friction. They will also lower the oil operating temperature. Now, I'm talking full rollers, like Scorpion 1000's, not those fosdick Comp roller tip units. Sling those over the fence and start over.

Absolutely no need for anything but a bone-stock oil pump in this build.

At 4500 rpm's, the motor will be suckin' in 454 CFM, so I see little need for a 750 carb, but if you already have it, use it. If I were doin' this, I'd probably use a 7101 Edelbrock intake and mount a 600 on it. The additional torque that a 7101 will make over the 2101 from 1500 to 4500 would be worth it for me.

 

You starting with a bunch of stock crap that should've been scrapped. The cheapest rebuild parts you could find and wanting 300hp before 5000rpm and 150000 miles under high loads and terrible conditions.

Simply put- it's not going to happen.

 

Ok. After reading your post's I have asked a few buddies around if they do have heads with Bigger valves, and bigger combustion chamber. Since the 032 heads with 1.72 valves are apparently not the hot ticket on a sub 5000 rpm Chevy 350.

The number on the block - checked again IS 397001 It seems to be missing the number 0 or 4. Might be a flaw from the factory. It shows now signs of begin milled off at least.

There's one friend who has heads with casting # 333882 and they have 1.94"/1.5" valves. And they would also get the pocket porting done to them along with the gasket match mentioned above. With their 76cc Chambers they would give me 9.04:1 compression according to this calculator here - Engine Compression Ratio (CR) Calculator That's with 0.040" gasket and zero decked block.

With those things sorted out, And since I still run the exhaust manifolds with fairly open 3" single exhaust. Would i be better set with Summit 1102 cam over the Crane Energizer 260 ?
With those better breathing heads 1.94" valves #882 would i now make my 300 hp goal below 5500 rpm ?

It's my understanding the the Quadrajet is a variable venturi carburetor. so it won't flow any more air than the engine really needs. And with the smaller primaries It still would get a decent mileage on the road. with a big performance boost when the big secondaries kick in the mix !
Also on top of all it works really well in harsh off road conditions.

 

The quadrajet is not variable venturi and it's not going to "give you a big performance boost", your engine would be just fine with a 600cfm carb, and some carbs may provide easier tuning- which makes more of a difference than "big secondaries".

The 1102 cam would work best in this application.

You're assuming 9.000" is "zero deck" with those pistons- may or may not be the case.

With good headers and tune, you may be close to 300hp, I wouldn't worry about the exact number too much though, you have a decent low budget "work horse" type engine planned and really it sounds like that's exactly what you need.


Very careful attention to machining and detail when assembling, frequent oil changes, and a spot on tune are what is required to get the 150,000 miles you're after. Most people don't use adequate oil/filer or change intervals, and keeping that carb in tune is going to be a continuous effort, you'll need a narrow band O2 sensor and a vacuum gauge wired into your dash at the very least, I'd also opt for a manual choke since this will be presumably used year round, especially in snow/cold which is one of the times when engines usually get too much fuel and wear the most. Cold startups are hell on an engine- may want to get a block heater too, they're cheap enough.

 

:thumbup:. thank you for getting those 1.72 valves off the 355. they are small even for a stock 305. have those 882 checked for cracks. I've found more cracked ones then good usable ones. they are no where near a performance head. but, I've had really good luck with them on heavy work vehicles. try to keep the lift under .450, they slow down fast with any thing higher. I've pulled rocker studs out of the with the 1103 cam. the 1102 cam in a 9.0:1 355 with 882's on top will be a good solid build, for a work vehicle. it will give up around 5200, but be strong at 1500-4500. good luck

 

Putting poor flowing heads on an engine is like sticking a half inch water valve in the middle of a two inch water line. Yes, the water will flow through it, but at a much lower rate than it enters. If you do a port job on the heads, it will still be restricted by the valve size, and whatever cam lift and duration is. Try to make sure it all matches, and works together.

 

For the use & power range you are shooting for,I'd ditch the carb altogether & go with EFI.Even TBI would work well for you in this case & be a lot more dependable.

 

Scrap the heads spending money on these heavy duty truck heads is about as useful as flushing your wallet down the toilet. The heads you have are intended for gas powered big trucks that move heavy loads at slow speeds with a goverened engine. One could say get L31 style Vortecs; the aftermarket offers many imitations of the GM L31 head that are much sturdier for about the same cost, shop around. This style head picks up a lot of power over the heads you have even ported with enlarged intake valves the L31 head will 40-50 horsepower all other things being equal. Some of that is better porting but most is in better combustion, they plain just get more work out of the fuel being burnt than any earlier head.

The heads, pistons, and cam all need to be thought of as parts of system. The cam timing, specifically where the intake closes, and the compression need to be calculated as Dynamic Compression Ratio. The DCR drives right on the Static Compression Ratio which is the computation of compression ratio based on the fixed volumes. This pushes the piston and combustion chamber choices as well as the deck clearance and head gasket selections to get both the correct compression ratios and squish/quench clearance.

The choice of split cam timing on the intake to exhaust to same timing is pretty much a marketing ruse. It's something that can get you into as much trouble by overscavanging the cylinder as not optimizing the scavanging. Overscavanging is very noticable as it will be a big hole in the power curve where underscavaging lowers the entire curve above the RPMs where flow becomes insufficient. Split duration cams are pretty safe with factory cast manifolds, unported heads with smaller exhust valves with single exhaust or duals with cat converters. With headers and highly efficient exhaust systems this type cam can walk you into strange tuning problems. You see a similar thing with high ratio rockers on the exahust as well where the mid range power is supressed a little and the power advantage only occurs way up in the high rev range.

You also have to be careful of cams with long ramps lower cost cams tend to stretch that ramp between zero lift and .050 inch for a great many degrees. At RPMs below the torque peak this can be very costly on power so pay attention to how many degrees are packed into those early ramps.

Bogie

 

I'm currently doing a full rebuild on a 1974 Chevy 350 engine.
This engine is going into a lifted 1984 Jeep CJ7 that's used for deep snow wheeling. So main concerns are rpm range from Idle - 5000 rpm. good idle quality. mileage and reliability Engine will run on 91 Octane pump fuel all times. And needs to last at least 150.000 Miles. I would also like to have around 300 HP with at least 350 Ft-Lbs of torque. and broad powerband.

The Jeep has TH-350 transmission with stock stall converter (around 1500 rpm) and has 4.10" gears with 38" Super Swampers.

Block has the number 397001. and has 4 bolt mains. Bored 0.030" over. It will be decked to 9.000" for optimum 0.040" quench. Oil drain holes will be enlarged.

The rebuild kit I will use on this project is from Summit Racing and includes hypereutectic flat top pistons. High volume oil pump. new bearings. gasket and everything that's needed for this "nothingspecial" standard rebuild.
The engine will have 9.25:1 compression ratio.

Heads that are on the engine do have # 3911-032 cast into them. they do have small valves 1.72" int / 1.50" exh. 70cc combustion chambers.
They do not appear to be the best factory heads GM made but I am going to reuse them anyway. They will get a home pocket porting job and matched to the intake gasket along with stiffer valve springs from Summit Racing for .490" Max lift.

Intake manifold is going to be Edelbrock Performer #2101 that will be port matched to the intake gasket. I will leave the heat riser open, but restricted a little bit. On top of the intake manifold will be a 750 cfm Rochester Q-Jet 4bbl carburetor.

Ignition is up to task and is taken care off by MSD 6A box and Pro Billet distributor and Vibration proof MSD ignition coil.
AC delco R45TS spark plugs.

I'm going to reuse the factory exhaust manifolds and the Jeep has a single 3" exhaust.

Now it's time to pick the camshaft. What i have been looking at are rather mild cams. I can't seem to decide what would actually be better for this engine a single pattern or dual pattern camshaft. And if there would be any gain with 1.6 ratio rocker arm's or even roller tip rocker arms ?

The cam's I like for this application at first glance are the following.

Crane Energizer 260 cam which specs at.
260/260 adv. duration
204/204 @.050" duration
.427/.427" lift
110 LSA
RPM range : 800-4500

Summit 1102 cam
278/288 adv. duration
204/214 @.050" duration
.421"/.444" lift
112 LSA
RPM range : 1500-4800

I have also been thinking about the Summit 1103 cam for a little more mid range punch ! But I also fear it might be on the larger side..
288/298 adv. duration
214/224 @.050" duration
.444"/.466" lift
112 LSA
RPM range : 1600-5200

Thanks in advance.

You're gonna have to open up that exhaust my friend. Air in- air out. Needs to flow. A budget set of headers and a couple open chamber cans will contribute greatly for a small cost.

 

old bogie brings up a good point about the long lazy ramp cheapo cams. heres some I pulled for you to look at and compare. these are very similar, either 1 of these will be good for your needs. notice the difference in the rpm operating range????? some of them lie, some are very close. notice the ADVERTISED DURATION????? this is what old bogie is getting at. the lower the ADV. DUR is, the faster the valves will open and close, building pressure, making power:thumbup:. but a lil harder on the valve train. I, myself wouldn't be concerned about being hard on the valve train with either of THESE cams. they are low lift, so they don't need big spring pressures to live. these cams will produce very similar power, pull really close the same vacuum. these cams will hit 300 lbs torq early, around 1700, peak torq around 3500, start falling under 300 lbs around 5000. still make good HP till 5200. that's a pretty good torq curve for a 9.4:1 355, old junk smog heads, 1 5/8" long tube headers, good flowing mufflers, high rise dual plane intake, and a 750 carb. the numbers will be less with stock exhaust manifolds. 9.4:1 comes from taking the 882's down to 72cc. it will work as long as you have the block decked, squared. and I see you will be doing that:thumbup:. whatever cam you decide on will need to be degreed in. nothing worse then putting a cam in and falling on it face because it wasn't degreed in. keep posting and asking questions. theres a lot of good advice here. as you can see, everybody is saying dump those stock exhaust mani's. get the most you can, out of what you got:thumbup:.

http://www.summitracing.com/search/...845542+4294891623+4294876876+4294881179&SortBy=DisplayPrice&SortOrder=Ascending

 

Just to clarify- adv. duration really doesn't tell you a damn thing about how fast the valves open and close. It COULD tell you how aggressive the opening or closing ramp is, assuming they're symmetric, if the adv. values are taken at the same lift spec, but they rarely are- especially when comparing "white box" cams.

In many ways the adv. values on hyd cams are close to useless. If you want real data you'll need the full cam print out- which is far more than you'l find on a "cam card".

Basically- don't get too caught up in any "advertisements".

Yea it sucks as it gives you less information to base a cam choice on, but would it be better to base your cam choice on "bad info" or "less info"? Neither is ideal but you have to either pick one or get a full cam print out- sometimes easy,sometimes near impossible.

 

yes , ap you are right. I should have said something like, "in simpler terms", or maybe some like "to make it easier for you to understand". but you should be able to see the OP clearly doesn't understand cam timing. my fault, calm down.

 

I was calm, no worries. :thumbup:

 

Harvey Crane originated the phrase "hydraulic intensity", which subtracts the 0.050" tappet lift duration from the advertised duration. He ground his cams for years and years on a HI of 62. In my opinion, that is still a good number to use, however some have the opinion that the number needs to be a bit smaller, with a more aggressive valve lift. While I can agree with that somewhat, current thinking dips the HI down to the low 40's in hydraulic flat tappet camshafts. This is a very aggressive grind that has the rim of the tappet almost ready to dig into the side of the cam lobe. While I can see that this would be advantageous if a fellow was running in a competition arena where he needed an extra 5 hp to drive around a competitor, it leaves me with a feeling that the motor will disassemble itself if everything is not exactly spot-on. It is certainly not the type of cam grind that I will recommend for a daily driver, where longevity is key. I can deal with an HI of around 50-55 for a street driver, but any less than that is just stupid in my opinion. An example of an HI of 55 would be 260 advertised and 205 at 0.050".

Crane Energizer 260 cam which specs at.
260/260 adv. duration
204/204 @.050" duration
.427/.427" lift
110 LSA
RPM range : 800-4500
HYDRAULIC INTENSITY 56, roughly in the ballpark.


Summit 1102 cam
278/288 adv. duration
204/214 @.050" duration
.421"/.444" lift
112 LSA
RPM range : 1500-4800
HYDRAULIC INTENSITY 74. A lazy grind.

I have also been thinking about the Summit 1103 cam for a little more mid range punch ! But I also fear it might be on the larger side..
288/298 adv. duration
214/224 @.050" duration
.444"/.466" lift
112 LSA
RPM range : 1600-5200
HYDRAULIC INTENSITY 74, again, a lazy grind.

While I agree that the L31 heads are the best cast iron production head that GM ever produced, they have several bad points if you're trying to use them without mods. They need guideplates to use rockers other than the OEM rail rockers that they came with. The pushrod hole must be enlarged. They need to be drilled and tapped for the guideplates. The large diameter of the valve guide boss needs to be cut to a smaller diameter so that you can use a decent spring with damper and positive oil control seal. The retainer needs to be changed for one that will allow more lift without banging into the seal. The stock L31 heads are available with the upgrades will cost over $1000 for the set, assembled. For another hundred bucks, you can get a set of Pro-Filer aluminum heads that will outflow the L31's by a wide margin and you can run more static compression ratio with the aluminum heads, so you can run more cam on pump gas.

 

I have NEVER seen a cam that failed on the opening ramp. Do you know where i can find a pic to save? It'd be a unique thing to see for sure.

 

are you sure????? if not, I can get us a cold beer. lol. btw, good point on those pistons. I was waitin to see if he was gonna ask you about them.

I got a question. I see that some cam companys measure adv. dur. at .006, then the same company will adv. another cam a .001. I think that makes a lot of confusion. I just wonder if summit cams are measured at .001 and that why it shows such a high HI ?????

 

yep, ADV durations aren't measured at the same lift EVEN FROM THE SAME CAM COMPANY. Giving you an inconsistent and useless "hydraulic intensity".

Also, this "hydraulic intensity" only give you a relative lobe speed in inches/degree from the first measuring point (say .006") to the second (.050"). Doesn't tell you a damn thing about the acceleration, jerk, or snap- NONE of which are a constant on any given cam lobe, all of which affect the "aggressiveness" of a cam.

I'll let TI try to explain what that means...

 

heres what I mean.

12-106-3 - factory Muscle™ - COMP Cams® has taken the factory muscle cam specs and reproduced them to our strict tolerances.

12-211-2 - Magnum™

two diff. cams, same company. measured diff for adv. dur. I guess that's why I look for the .050 when comparing cams

 

OEM GM heads unported always need dual patterns.

 

I’m gonna throw in my two cents to the OP for what it worth. I’ve used a Comp. Cams High Energy 260 (212 @ .050” , .447”lift) in a 350 for 14 years without any regrets until I quit using it. Pulled 15” of vacuum at idle and pulled great from a dead stop with stock torque convertor and a 600cfm vacuum secondary Holley. I admit it was with a 3.73:1 gear with stock tires.
You may want to consider the High Energy 256 with those big tires. Not to confuse it with the Xtreme Energy line of cams. Xtreme Energy = extreme wear & noise IMHO.
To be honest you would be much better off going with a roller cam if your hoping to get 150K out of it. The flat tappet cam wasn’t designed with todays oils. That’s why all the automakers are using rollers. I know the lifters are so much more expensive, but its gonna be worth it 150K from now.
Just getting an engine fired-up the first time for the newbie can ruin a cam. If there is something overlooked like getting the ignition timing off a little(or a lot), or not having the carb primed, ect,ect and taking too many revolutions using the starter can wipe-out a cam before it even has the chance to be broke-in. Even if it fires-up the first time there is a good chance that it can go flat. It would be a shame to put so much money into an engine just to ruin it before you get 1K miles on it. Do yourself a favor and google “camshaft failures”.

FWIW
Good luck!
ssmonty

 

I agree. If you can't do a roller at this time. Save your money. Long term you will be money ahead with a hyd roller on the street.

 

To the op: if you're considering what someone suggested about fuel injection I bought the 350 I'm building out of a jeep. It came as a complete corvette tpi motor with Injectors, computer, wiring harness, aftermarket intake, distributor, tb, shorty headers. All I wanted was the long block & accessories but the price was right. Pm me if interested...cheap. If not I apologize for trying to hock my wares on your thread

 

a retrofit roller cam and lifters would be the best:thumbup:. if the OP went that way, he could save up for better heads. them old smoggers , might get by. but a roller cam and quality heads would get him to 350 torq/ 300 hp with ease.

 

Maybe its because I'm extremely cheap, but for a very basic build like this I wouldn't have any problem using a moderate hyd flat tappet cam. One of those $75 white box specials. I haven't had problems with them when used properly.

We're talking about a $100 cam kit and $40 set of springs with the heads he already has VS a $800 cam kit and $1200 heads... Most of the jeep guys I know don't have $1200 in the entire engine.

Is it perfect and ideal? No. But it works and its cheap. I'm not a cam guy like Chris, and I'm not a pro engine builder, but i am a guy who understands having to fit the autoparts bill in between the groceries and electric bill.

Sure he may only make 280hp, BUT he'll be out there in the snow screwing around in his Jeep having the time of his life instead of trying to beg, borrow, or steal $2K to finish an engine. This is OBVIOUSLY a low buck build here.

 

Maybe its because I'm extremely cheap, but for a very basic build like this I wouldn't have any problem using a moderate hyd flat tappet cam. One of those $75 white box specials. I haven't had problems with them when used properly.

We're talking about a $100 cam kit and $40 set of springs with the heads he already has VS a $800 cam kit and $1200 heads... Most of the jeep guys I know don't have $1200 in the entire engine.

Is it perfect and ideal? No. But it works and its cheap. I'm not a cam guy like Chris, and I'm not a pro engine builder, but i am a guy who understands having to fit the autoparts bill in between the groceries and electric bill.

Sure he may only make 280hp, BUT he'll be out there in the snow screwing around in his Jeep having the time of his life instead of trying to beg, borrow, or steal $2K to finish an engine. This is OBVIOUSLY a low buck build here.

and when you have to do an oil change and the oil cost as much as that white box cam, you figure out why flat tappet cams are cheap now..

 

Accel oil at walmart is under 3 bucks.

 

I doubt most people have a 9 qt. oil system. Most will be 5-6 qt. systems, so it's even cheaper. Not fair to compare a oil system that large too what most people have.

 

AND most street driven 8qt systems don't need to be changed every 3,000 miles.

So really you're looking at about a $3 difference per oil change, maybe as much as $10!!!

 

DANG!!! we musta scared the OP off lol. we went from a good, solid, dependable, fun build to a roller cam, aluminum heads, and 9qt oiling systems. that ole boy is gonna be so confused, he'll end up going with those 1.72 heads. I hope we didn't run him off, lol

 

Yeah, but it sounds like if he goes to a roller cam you can run the engine without oil! Imagine how much he'll save on those pesky oil changes then!!

 

I thank you for the information given into this discussion.
This engine will use a mild flat tappet camshaft as mentioned previously. This engine has to idle smooth at 600 or so rpm and have a relatively broad power band with strong low to mid range torque.

The durability of 150.000 miles is maybe a touch too much to ask for, however it must run trouble free for at least ten years with proper service of course. given it probably won't even be driven more than 6000 miles per year !

 

I would go hyd roller. With lifters we have today and oils a flat tappet will last you about 15 to 17K miles before it goes.