I passed on a LS, too complicated , too many things to screw up.I looked briefly at mods done and things like changing injectors etc = too much $$$.
I thought a 383 would pull a tall gear easier than a 350.I'm thinking 3:08 or 2:73.I had a 74 Vet and no matter how fast I drove it got about 25MPG. Ted

Did you ever say what car this is going in? Weight of the car makes a big difference in what you do too. Good MPG is a relative term! I get about 14MPG in my 96 K1500 with a lift kit and 305/70 tires. I think thats pretty descent, but others aren't happy unless they are getting over 20mpg. If you stay with a mild cam and the rear end you are talking about and are workin on a mid size car and not an Impala or a pickup, you can probably get between 14 and 18 when you aren't beating the bejesus out of it. If milage is your #1 objective, then just go basically stock. Low compression small cam small cubic inch = good milage and no fun
L8r

There is one more step in horsepower you can go and it is more expensive than a 383 but try taking a 2- bolt main 400 small block-use 350 crank and rods- 400 pistons AND special main bearings that are thick shell to make up the difference (.200)-as long as you don't excede 600 horses you don't need to get the main bearings splayed--really expensive--what you come up with is 4.125 bore x 3.480 stroke= a really big nasty adult version of a 327--superior bottom end torque from idle to whatever-will eat 383's alive as short stroke will grab rpm faster and higher than long stroke- the main bearings are around $169-$209 a set but for every day street driving but all the ponies you would ever need--it works-- ps federal mogul stocks the bearings

again, the only reason people build 383's is because they don't have a 400 block. If you have a 400 block, why in gods name would sacrifice 23 cubes and put a 350 crank in it? Its probably more expensive than just building a 400, and you're going to feel like an idiot when you line up on the strip and some guy who just built a 400 for 2/3 the price of your 377 hands your butt to you on a silver platter.


Destroking is stupid, at least barring really strange circumstances like CID limitations.

K

The strips around here are starting to see more and more of these "stupid destrokes" and even more and more of the 372-382.9's- why - its's simple- faster response and torgue all the way from start to finish- thats what made the 302 and the 327 such good engines. Long strokes top out on stability at about 5 grand- not so with short strokes- it's simple engineering principles. They are even making 427 small blocks now- thats a little crazy but they sure do run ! SB 400 was a good motor for torque and pulling but not real great for pure performance- if you have ever ran a 327 you know what they can do- it was a motor that just wanted to run-- you didn't need big cams-headers- and 1000 plus cfm carbs- just dual exhaust and a decent quadripuke and it flat got with the program . Real cheap bang for the bucks !

You know the rule that says there is no replacement for displacement. Forget that and go learn about rod:stroke, piston speed, and some other terms that you have probably never heard of and then come tell me that a 377 is a bad idea.

Whoa Dude! Take it easy on Killer Formula! Short stroker motors accelerate quickly in light vehicles and with big gear ratios, but have you ever driven a full size Chevy 4X4 with a 327 and an automatic tranny? I think I could make more power with a 6 cylinder! (probably not, but you get the point). It all depends on what you are doing with the motor, and what RPM band you want to make power. If all things were equal, between a 377 and a 400, and you had them both on an engine dyno, I would have a hard time believing that a 377 would make more torque! Show me the numbers!!

400's have bottom end torque-excellent for pulling and towing-but 377's have bottom end through the ceiling--a good rev limiter is advised- I know of a 73 Chevelle in Vegas that is on it's second B&M trans in a year (Street racing ) as well as daily driving . They put it on a dyno and told the guy to get a 400 turbo or a 4-speed trans because the motor is making too much torque- it is only putting out 570 ponies but it has also shattered a 4:11 posi rear end . I have never heard of a 400 doing that- true it gets run hard but it loves to run--face it a long stroke is good for pulling but - it can't out perform a short stroke running the same bore . Think of how long it takes the piston and rod to travel that extra distance- a 383 is an example of an engine that would benefit from a high set of gears because it pulls harder than a 350-- thats one of the reasons 400's were put in trucks-more bottom end power than a 350 . 377's weren't designed for trucks- they were made for street or strip performance not pulling a truck but if you put one in a truck-- I would bet it would get with the program .

I've studied all those issues and more, noob. If you think you're going to beat a 406 with exactly the same parts as you built your 377 you have your head seriously lodged in your rearmost orifice.

Do a search on this board, I know all about how longer rods influence more dwell, and a better burn. And its not piston "speed"genius, take a physic class. Its Piston velocity and studies have shown for street motors it doesn't make a whole lot of difference.

BTW, a 350 (327 crank in a 400 block) has a better rod to stroke ratio than either of the motors that you're talking about. That doesn't mean its going to beat a motor with 50 more cubes!

Good lord, some dude reads a 3 paragraph article about piston velocity and rod to stroke ratios, uses a term incorrectly and thinks he knows everything. You got a lot more reading to do, and more importantly motors to build.

K

Well, as for the fellas question.

If you plan on building it yourself you can definately build a decent 350 or a 383 and do very well with it. The 350 will be the most cost effective since you already have the crankshaft for it.

Spend you're money on the machine work and use a reputable shop. Have the block zero decked, that means the top of the pistons will be level with the blocks deck surface at TDC. This will go a long way towards helping you achieve your goal. Better quench means better combustion. Better combustion = better economy and performance.

If it's at all possible, find a set of Vortech heads from a late model truck. They have much better ports and combustion chamber designs and will likely need less attention from the machine shop. Have them cleaned and install the springs recommended for use with your camshaft. Do not let them monkey around with the valve job unless it's necessary and you know for a fact that they can duplicate GMs work, The general did some homework in this area and applied it to these heads.

Pistons, by all means keep the compression under 10-1. More than this will require a larger camshaft to keep you out of
detonation and it will kill the low speed power you want. Pistons with a 12cc d-shaped relief for the 350 and an 18cc relief for the 383 with a zeroed deck and a 0.041" thick gasket will put the comp. ratio at 9.7-1 for both engines. If you decide on a 383 a larger camshaft will work fine. The extra cubes actually need it to keep cylinder pressure in ping free territory.

Camshaft, if your budget allows it, get a hydraulic roller. If not then just use a hyd. flat tappet. Be sure to pick one with the LSA
at 112-114 preferably the wider of the two. The duration will be the tricky part, err on the small side of this figure and you'll be happier. 255-265 degrees total based on where your compression ratio ends up would be a good starting point. Keep the lift and 0.470" or lower for the Vortech heads, more than that will require more machine work and use money that could be spent elsewhere. If you decide on a 383, add 8-10 degrees to the duration numbers and you'll be in the ballpark.

I hope this helps a little in the decisions you have to make. Good luck with the engine.

Larry

Although it is possible to build a 383 for little more than a 350 like many things in live it usually doesn't work out that way in the end. What starts with a simple stroker crank purchous oftain gets people carried away on expensive rotating essembles. Personally for a budget build I would build a 350 and use the extra money on better heads.

ask yourself a few questions before deciding on what to do,

do you really have the need for the larger displacement? or is it cooler.


i looked into a 383 stroker, and a 400 SB for my caprice. after contemplating so much i decided i would buy the parts i wanted anyway and stick it in the 305 i had laying around to get the car running (im not generally a chevy man.. im an AMC/Jeep guy, never worked on a SBC)

so for a good test bed for myself i ust built the 305 since all SBC's are so similiar


stuck a mild cam, edelbrock Intake with an edelbrock 750. i did a few other odds and ends, cleaned up the flow of the heads, installed heavier springs, new rockers and pushrods .

my 305 now pushes out about 330 HP

is it the fastest car with the most axle snapping torque? of course not, but it was the cheapest performance engine buildup i had ever got myself into.

since your looking primarily to cruise, this would be a great start, and if your unhappy with the performance.. you can always throw those parts on a 350

just my 2 pennies

Id be interested to know more of the specifics of this build...

BTW, I think you'd be much better off with a 600, 750 305 caprice sounds like a bit much...

K

i'll get a list up and post it up..

sorry i mistyped, im using a 650cfm

the factory Q-jet was a 650 as well

Wow 330HP's out of a 305? That would take a little more than a mild cam and an Edlebrock intake. I'd like to see the specs on that one too!