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Old 05-18-2020, 09:56 PM
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Arrow 496 build questions

Sorry, looks like this will be a long post. Just trying to make sure I get all the info and thoughts out there.

Some background info:
Was going to do the LS 6.0 route, but came across a good deal on this. I like keeping some of the old school muscle with some new systems (with with EFI fuel setup). 1989 454cid w/tbi manifold out of a dually truck. 2 or 4 bolt, haven't opened up the pan yet.
Vehicle it is going into:
1967 El Camino currently has 396cid. Turbo 400 transmission (will get a 4l80e at some point) and 3.30ish gears. (3,000ish RPM @ 70mph on 295/50 r15)
Goals for this build:
95% street 4% towing (have a classic camper trailer we need to put to good use) 1% strip

I'm not a min / max type of guy. If I can get this build close to 600hp I'll be more than happy. However, I do want to leave a little room to grow in case I decide I have too much money and put NOS or a turbo on it at some point. 'Cause who doesn't love a turboed big block.
With that in mind. I need some help on the compression ratio. This is for pump gas so I believe I should aim for 10:1 or maybe even 9.5:1.


  • Heads: ProMaxx 317 (I've also looked at Summits iron heads SUM-152125 and the Flo-tek 315)
  • Intake: Weiand Stealth #8018
  • Rotating Assembly: Eagle B18022L060 forged 18cc pistons cast crank.
  • Cam: Clay Smith 229/241 @.050 along with a set of his roller lifters.
  • Rockers: Comp Ultra-Gold Aluminum
  • Oil pan: Milodon 30951
  • EFI / Fuel: Super Sniper 1250
  • Fuel Pump: Holley In-Tank RetroFit 450lph
  • Distributor: Holley Dual Sync
  • Other nickel and dimes: Timing chain, plugs, wires...

I upgraded to the big boy size fuel setup. Just felt I was getting close to the 650 Naturally Aspirated limit of the normal sized Sniper / fuel pump. Last think I want to do is spend all this money then find out I don't have enough fuel. Or am I over thinking this? Only about a $600 difference.

Thoughts, questions, or concerns?
Anything I completely overlooked?
What should I used for a converter? Stall speed?
Would it be better or go with the oval port heads?

Thank you in advance.

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Old 05-19-2020, 12:29 AM
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If you're positive you want a charger, drop your compression down to the 8's now, or the motor comes back out to change pistons. I'd recommend 4 stud bottom end as well, plus head studs. All forged rotating assembly as well. No sense building twice.


If you don't want to fool with all of that. 10:1 with aluminum heads 9.5:1 with iron, that'll keep it from pinging to death.

Here's a couple things that might cause some pain, headers and oil pan.

Headers first, if your 396 has headers already, see how much room you have between the steering shaft and #3 and #5 tubes, if it's tight now, it'll be worse with aftermarket heads, they have raised exhaust ports, some have no issue, some have a nightmare. I used the Brodix race rite oval ports which have stock height exhaust ports, still had to ding 3&5 tubes for clearance.

Oil pan next, you'll need a stroker oil pan, moroso 20403, and 20408 are common, I have the 20408 and had to notch the crossmember for it to fit without rubbing. Again, some have issues, others not. The 20412 I believe has a shorter sump, but has the kick outs on the sides, might make changing oil filters a pain. Milodon, B&B, are other pan sources.

You may want to think more towards a truck type build if you're pulling a camper. I don't have enough sense to tell you how to do it other than more cubic inches.

My 496 is in a skylark, th400, 3.08 rear gear, real similar to what you're talking about, cam is smaller 225/235, no clue on power, but it can get real scary in a hurry, and isn't a pain at all to drive in traffic.
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Old 05-19-2020, 06:01 PM
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95% street. Stop right there, there's your build.......... Also, forget the duality build, either it's naturally aspirated or it's artificially aspirated. They're two completely different builds.

Airflow Research #3610 heads, 109cc chambers
Intake: Weiand Stealth #8018
Rotating Assembly: Zero deck. 12cc piston dome, Fel-Pro 1017-1 head gasket
for 10.43:1 SCR and 0.039" squish/quench......10cc dome, Fel-Pro 1017-1 head gasket for 10.26:1 SCR and 0.039" squish/quench......8cc dome, Fel-Pro 1017-1 head gasket for 10.10:1 SCR and 0.039" squish/quench.

Cam: Howards CL122115-12 Retrofit Hydraulic roller cam and lifters. 278/288, 225/235, .595"/.601", 112 LSA, 108 intake centerline.
1800-5400 RPM operating range, fair idle, street & mild performance usage. Crisp throttle. Beginning to make power at 1800, this cam will pull in 4th gear at cruise. If you use more cam than this, it will not be making power at your cruise rpm's. Study it for yourself. Every cam out there has a definite OPERATING RANGE. You can't cruise at 2000 using a cam that makes power from 2500 to 5500. Well, you can, but fuel mileage and power will be in the dumpster.

Rockers: Comp Ultra-Gold Aluminum
Oil pan: Milodon 30951
EFI / Fuel: Super Sniper 1250
Fuel Pump: Holley In-Tank RetroFit 450lph
Distributor: Holley Dual Sync
Other nickel and dimes: Timing chain, plugs, wires...

I upgraded to the big boy size fuel setup. Just felt I was getting close to the 650 Naturally Aspirated limit of the normal sized Sniper / fuel pump. Last think I want to do is spend all this money then find out I don't have enough fuel. Or am I over thinking this? Only about a $600 difference.

I would feel OK about this big boy fuel system.

One more thing, I would use a 28" tire on the rear, with a 3.55 gear.
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Old 05-19-2020, 06:55 PM
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Flo-Tek 290cc oval would be a lower cost alternative to the AFR ovals if cost is a consideration.

Your usage to me doesn't say "Rectangle Port" at all.

if your rpm and mph figures are right, the factory gearing available would 3.31 for a 12-bolt or 3.36 for the 8.2" 10-bolt.

If you swap to an overdrive trans, you are going to need to change rear gear to 3.73 or more at the same time, or the cruise rpm is going to drop too low for anything but a stock/near stock camshaft.
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Old 05-20-2020, 07:56 AM
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Fair points made.

techinspector1, Thank you for the info. It's just going to be naturally aspirated. Turbo deal was just something that got carried over from the LS builds I been looking at. I'll be sure to check out the cam and heads.

ericnova72, I'll check out those Flo-Tek heads also as the cost is always a consideration. Just trying to be smart with the money spent and not just go cheap. The trans swap wont be for awhile. Heck, might be a little time before I get started on this build. There might be some error in those rpm & mph numbers, but should be close. It is just a 10 bolt read end.

Question about the machine work. I understand what zero decking is, but why is it important (better?) over just using piston with a little larger dome?

I think you guys have helped out on every post I've made over the years. I do appropriate the experience and help.
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Old 05-20-2020, 08:31 AM
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Just trying to wrap my head around this a little better. I been trying to look and understand numbers.

In my 396 I installed a Comp Xtreme Energy
Lift: .510"/.510"
Duration @50: 212 / 218
Duration: 264/270
Lobe Separation Angle: 110
RPM Range: 1200-5200


Howards Cam
Lift: .595" / .601"
Duration @50: 225 / 235
Duration: 278 / 288
Lobe Separation Angle: 112
RPM Range: 1800 to 5600

I been very please with the drivability of the 396. Even more so since I got the cooling under control. The Clay Smith cam didn't list a range, just the max of 5700 rpm.

It looks like the Howards cam is just a step up from what I am using now. Given the 100 extra cubic inches of air in and out should give the same type of street manners, right?
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Old 05-20-2020, 11:08 AM
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The rpm range on the Howard's cam is for a 454, so it'll start working a couple hundred rpms less in a 496. That is the exact cam I have, as far as street manners, grandma could drive without issue, idle isn't wild, but it doesn't sound stock at all. Mine pulls to around 5700rpms then noses over, plenty for the street.

Mine has an 8.2" 10 bolt, still holding up fine, just stay off the strip till you have the money for something stronger.


Piston tops on zero deck is detonation protection, allows you to use the headgasket to set quench distance vs just making due with lower total timing, lack of performance,etc.. I don't know the technical details on it, but read around, several excellent write ups on the subject.

Last edited by Dfish1247; 05-20-2020 at 11:16 AM.
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Old 05-20-2020, 11:32 AM
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Quote:
Originally Posted by Chucky5150 View Post
Just trying to wrap my head around this a little better. I been trying to look and understand numbers.

In my 396 I installed a Comp Xtreme Energy
Lift: .510"/.510"
Duration @50: 212 / 218
Duration: 264/270
Lobe Separation Angle: 110
RPM Range: 1200-5200


Howards Cam
Lift: .595" / .601"
Duration @50: 225 / 235
Duration: 278 / 288
Lobe Separation Angle: 112
RPM Range: 1800 to 5600

I been very please with the drivability of the 396. Even more so since I got the cooling under control. The Clay Smith cam didn't list a range, just the max of 5700 rpm.

It looks like the Howards cam is just a step up from what I am using now. Given the 100 extra cubic inches of air in and out should give the same type of street manners, right?
I'm trying to keep the combination in synch when you opt for the 4-speed auto. You want to keep the lower end of the cam's operating range in tune with the crank rpm's at cruise. If you are going to keep the 3-speed auto, then use all the cam you want to, but if you are going to swap to the 4-speed, you will want to keep the lower end of the cam's operating range UNDER the cruise rpm's. If the lower end of the cam's operating range is OVER the cruise rpm's, then you will be operating in the UNEFFICIENT range of the cam, not creating as much power or as much fuel mileage as you could have if you had used a cam that made power UNDER the cruise rpm's.

Zero deck to allow use of pump gas without detonating the motor. Use the tallest piston you can find (compression height) to allow minimum cutting of material from the block deck. This has nothing to do with static compression ratio, which is dependent on the crown of the piston and how much dome is used. It is about the measurement from the center of the wrist pin to the crown of the piston just above the top ring, not having anything to do with dome. Check with Skip White Enterprises, he has made a deal with Wiseco to manufacture pistons with another 0.010" of ring land height (compression height) so that the decks can be cut to zero without taking too much off the decks. In other words, the STACK of parts is taller, requiring less material to be removed from the block decks in order to reach ZERO deck.

Try not to let someone talk you into more cam than you need. Heck, there have been literally millions of BB Chevies that did a great job of pulling on the street and hauling a load WITH A BONE-STOCK CAM. Jeez, I get so tired of hearing MORE CAM, MORE CAM, MORE CAM. Some of you guys need to try putting a nice driver together for once, instead of a fender-shaking mess that has no low end without using a 3K or 4K converter.

Also, I am all about using AMERICAN MADE PARTS. To heck with these Chinese junk parts and making a profit for a group of Communists who hate us and have cost business for the entire world with their stupid, inept handling of the current virus epidemic. I will never buy anything else that is made in China or any other Southeast Asia country, because China uses countries that surround them to make products too. MADE IN AMERICA is the answer for me. If we all pull together, we can put America back on the manufacturing map.

.

Last edited by techinspector1; 05-20-2020 at 11:56 AM.
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Old 05-20-2020, 06:18 PM
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Who does not like a turbo big block?
<<<This guy.
After your 3rd or 4th headgasket goes you will understand why I love OHC 4 cylinders so much.

With a turbo your going to want efi and fully electronic timing control. It can be a block saver over a dumb engine running blowthrough tech from the 80's.
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Old 05-20-2020, 07:15 PM
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I'll be going EFI with timing control. Upon reflection I'm not going to go with a turbo. I just don't want / need that much hp in a driver.
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Old 05-21-2020, 03:35 PM
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Quote:
Originally Posted by Chucky5150 View Post
I'll be going EFI with timing control. Upon reflection I'm not going to go with a turbo. I just don't want / need that much hp in a driver.
Yes a NA 496 will give you more then enough grunt to break stuff while being so much easier(cheaper) to dial in constant numbers.
Now you need to ask yourself do I want this to be a high compression high rpm motor possibly setup for e85 or lower compression(8.7-9.5) longer life at the cost of some horsepower?

The engine is just a part of the drivetrain. While it is cool to say you put 600 at the crank if that doubles or triples your budget to support that 600 with "built" parts you may find you need to baby the drivetrain. Vs having say 450hp and being able to use all of that without risking breaking all the time.
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