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Charliedclayton 08-20-2010 11:55 PM

SBC 377 Build ?
Hello Im new to the site but have used this to answer many problems Iv come along. Im about to turn 19 and getting ready to put together my first engine build, its a 377 stroker. It's going into my 82 Chevy C10 longbed and with a new richmond super t-10 transmission...I live in town but walk to work(right down the street from me). So it's going to be more of a weekend blast then anything with limited drag strip use. Im shooting for a budget of $4000 for the engine its self and not in a hurry with it being my first build, my problem is with getting info over the 377. Just about every website that has talked about it always brings up the 377 as useing the 400 block and 350 377 is a 350 block and a 400 crank(how I bought it), the guy told me it "came outa my uncles old bread truck" and I picked it up for $150 and just was told it was a wore out 350.
Everything inside was new but the cam(no idea what it is) which had some good wear on it. But anyway Im really only worried about how this 377 is different then the 400 block/350 crank combo is....Iv never found anything about this combo or how it reacts on the street/stip. Has anyone done this type of build or know anyone whos done it? I really want to keep it like it is and not bore it over to 383 before anyone brings that up.
Any info over this would help a lot.

ericnova72 08-21-2010 01:17 AM

You have what is commonly known as a "383 stroker" to hotrodders and racers, which is built from the 4.000" bore 350 block, your block just didn't need boring .030" oversize so the cubic inch comes out to 377 - a 4.000" bore x 3.75" stroke(math = 376.99). The common 383 would be 4.030" bore x 3.75" stroke(math = 382.66).

The other 377 you refer to is correctly called a "377 de-stroker", it starts with the much bigger bore 400 block which is 4.125" bore stock. You remove the stock 3.75" stroke crank and use the 3.48" stroke from the stock 350. At standard 400 bore size of 4.125 x 3.48 stroke it is 372 cubes(math = 372.05), most blocks need to be bored to .030" oversize due to age and mileage, so 4.155" x 3.48 = 377(math = 377.48). The shorter stroke is supposed to tend to make this a better high rpm engine, but that is splitting hairs. Its larger bore size does allow big heads to breathe better however.

If you just call yours a "383" everyone will know what you are talking about - a stroked 350 block. If you call yours a "377" most rodders and racers are going to think you have a 400 block based engine.

You have what is just basically a 383 minus the bore job, it will react to parts just like any 383 combo will. No magic, no mystery.

454C10 08-21-2010 07:37 AM

A little fyi.

power is in the heads. spend the money on heads first and cubes last. A 350 is about the cheapest engine to build.

I would much rather have a regular 350 with a good set of heads than a 377, 383, or 406 with a set of crappy stock heads.

you will have better results if you start out with a complete vortec 350 engine (96+, factory roller cam engine) for 500 to $750. get a complete engine from fan to flexplate (including the starter, belts, pulleys, and all the accessories. And vortec heads are decent with a little work. So, staring with a vortec 350 gets you a newer block, good set of heads, and a factory roller cam setup. You can reuse the stock roller lifters, just add a bigger cam and not worry about cams going flat with todays crappy low emissions oil.

do a regular rebuild on a votec 350 engine, add a little more compression, do a little head work, add a bigger cam, stronger valve springs, roller rockers, holley 750cfm 3310 carb with a vortec rpm intake. Can easily make 400hp+/400 ftlbs+

Also, a bigger cam requires more gear ratio. If you plan to stay with the stock gearing then you should not add much more cam or compression.

A Limited Slip center section is always a nice addition to a truck. Nice to be able to apply the power to the road. So save some money for that.

Charliedclayton 08-21-2010 03:32 PM

Ah I was wondering why I couldnt find the "377" stroker really any where. I may end up boring it after all but not 100% sure on it. The bores are in great shape as they are and I just like saying its a 377 lol. And for $150 Im going to keep with this engine, I thought about vortec 350's but found this one for as cheap as it was I jumped on it. Then having found out its already got near all the inside parts new but the cam and heads/intake-carb along with it being a stroker...I was told I did very well for the find. With my set budget of $4000 Im shooting for mid 400hp with the engine, I know 383's make this type of power with out to much of a problem. Iv thought of going with the Edelbrock top end kit for 383 strokers thats rated at 460/460-hp,tq with 9.5 compression. I'll be running 93 oct gas from shell all the time, so would 10-1 compression work with 93? I live in south Texas so 93 oct is every where.
My truck already has a limited slip and 3.73 gears(from my last 82 chevy c10) and Im moving all my suspension upgrades over to the new truck so putting power to the ground is not a problem.

ericnova72 08-21-2010 04:20 PM

I agree, you made a good score, and you are right that there is no sense boring it if it doesn't need it. It is just somewhat rare to find a block that doesn't need boring unless you buy a new block, that is why the majority of this combination are 383 cubes, and why it is most commonly referred to that way.

Nothing basically wrong with the Edelbrock package if you like it. You could pick and choose different parts from different manufacturers and do better both cost and hp-wise if you want to put in the time and effort to search.

10-1 will be fine with aluminum heads on pump gas with a cam size like the Edelbrock package has, or similar or larger, just not any smaller cam.

Charliedclayton 08-21-2010 09:29 PM

I still havent picked a way of putting together the top end, with the kit i'll at least know the area of power im making(should) till I can put it on a dyno. With it being my first build Im not wanting to mess it up so keeping it simple for now....out of the whole build for the truck, the engine is what im putting most of my time into so I want to get it right yea know? Body wise it just need a new door and some paint. It just has a 305 that came out of a car in it right now :/

Duntov 08-21-2010 10:33 PM

First thing to do if you don't already have one is to get a dial caliper and see if the block is really 4.000". I would then get the numbers off the crank and pistons and post that. Also I would measure the rods and see what they are.

Charliedclayton 08-22-2010 11:39 AM

The stroke is 3.75 and the pistons im getting rid of due to chips(when we took the engine apart my father just let them drop on to the floor) on a few of them. Ill get the crank number later on tonight and I never thought of using a dial caliper, I just used a ruler :smash:
As for the rods Ill get that to, there new like most of the parts we found inside.

Duntov 08-22-2010 11:49 AM


Originally Posted by Charliedclayton
The stroke is 3.75 and the pistons im getting rid of due to chips(when we took the engine apart my father just let them drop on to the floor) on a few of them. Ill get the crank number later on tonight and I never thought of using a dial caliper, I just used a ruler :smash:
As for the rods Ill get that to, there new like most of the parts we found inside.

The #s off the pistons along with the crank would be helpful to give us an idea what it was. 383 is thought of as one of the best combos.

Charliedclayton 08-23-2010 07:42 AM

numbers i got off the crank are 89882442 with a m7 on it
pistons all say "ind bras" on one side-the other reads "m15"
then bottom side says "p-1505"-other reads "R"

i think these are the numbers you was talking about

cobalt327 08-23-2010 07:53 AM

Only crank # close to that in my info is 3932442 305/350 '69-'85 2.45" main/2.10" rod journals 3.48" (350) stroke, cast iron.

OEM 400 crank: c/n 3951529.

Charliedclayton 08-23-2010 08:01 AM

i dont think this crank shaft is oem at all. everything but the heads/intake/cam looks new and hasnt got real if any wear on it at all. iv looked up the crank numbers and havent found anything at all, but in full rotation the pistons travel 3.75 inches total from top of stroke to the bottom

turbolover 08-23-2010 08:29 AM

How are you measuring the stroke? FYI if you use good oil you can run an engine a million miles and the crank and rods will still look brand new.

And in most cases painting will be a lot more trouble than building an engine. At least in my experience.

Charliedclayton 08-23-2010 08:38 AM

ruler tool we have, both with the pistons on the crank. from top to bottom i get 3.7 and a half. then with them out, i can get at the wear part on the side of the cly...from top to bottom its still 3.75.
and yea painting will come later on but not that big of a deal to me just yet.

turbolover 08-23-2010 08:54 AM

Sounds like you may just have a 350. Incorrect measuring can add .25".

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