Brettmc

I'm toying with the idea of building a 383 lt1 with the intention of 425+ rwhp. I'm thinking I need to start with a 4-bolt block but will a 2-bolt be reliable at this hp level? This will be mostly street-driven will very few trips down the quarter.

Brett

Pete K

In my opinion, a 2 bolt is fine. I run one in my own car.

aboatguy

All corvette LT1s are 4 bolt main. Horsepower doesn't kill engines revs do. IMO for 425 at the tires with a stroker is not really going to stress the engine however, with a 2 bolt block at the bare minimum I'd use studs, but I always go for overkill, and I'd probably spring for splayed 4 bolt mains.

MIke

Brettmc

Thanks.

aboatguy

There's some cats on Camaross.com and LS1tech with stock F-body/B-body shortblocks and hairy head cam packages on DD cars that are putting 400 rwhp or more so as PeteK said you should be good to go. I don't have that kind of luck so I overbuild them and hope they survive me beating them like I'm a pimp and the cars been withholding my money!

Mike

Brettmc

What would it take to achieve my HP goals with a stock rebuilt LT1 bottom end?

Mojave

425 RWHP on a stock bottom end isn't impossible, but it's no cake walk either. Put some good heads on it (LE, AI, AFR, etc) and a healthy cam.

Another vote for 2 bolt.

Brettmc

That would be much cheaper than a 383 build...and the engine can stay in the car.

Brettmc

Are we talking some 195cc heads? What kind of .050 duration are we talking? upper 230s?

BLOCKMAN

The 3.750 stroke is alot harder on a 2 bolt main then using a 2 bolt with a 3.480 stroke crank.

We have installed lot of splayed caps on those block for guys over the years.

Golens engines builds alot of those engines and the add 4 bolt caps to they 383 builds.

http://www.ls1tech.com/forums/advanc...ever-seen.html

http://forums.corvetteforum.com/c4-t...ps-1992-a.html

The engine in this link was only bolt 3.480 and the caps were moving around thas why the bearings in the main caps look like shyt.
http://www.camaros.net/forums/showthread.php?t=170780

Crepitus

http://www.trickflow.com/egnsearch.a...5&autoview=sku

Brettmc

Interesting reading. If it's put together right, stock/cast stuff will last a while for my intended purposed. I think I'll go with a head/cam swap and see what happens.

Mojave

430 CHP is certainly not 425 RWHP.

Brettmc

Advanced induction has some attractive head/cam packages. I bought a set of used 643 heads today for $75. They will either be sent to AI as cores or I'll get someone to hog em out.

Brett

Crepitus

quite true but on a 383 it should be in the ball park.

tpi 421 vette

A 4 bolt block is nice and usually preferable.But a 500 crank hp engine with a 2 bolt main block should be no problem. I have pushed 2 bolt main blocks way past that.

BLOCKMAN

Not to start a flame here but I have built a lot of engines over the years and have never seen a 500 horse 2 bolt work as we sure have put on a lot of splayed caps on those blocks because of the caps moving around.

But of course I get calls about why this failed and why that failed and I get a lot of calls about this subject.

I have a 5 gallon buck fo old 2 bolt caps that look like theye have been welded on broken ones.

I have seen guys try to strap, stud, pin 2 bolt caps tring to get them to work. If 2 bolt blocks we that good GM would have never made a 4 bolt block mains.

Going to a stroker really tries to push the 2 bolt caps around but most guys don't understand that because they read it in a magazine they made 800 horse with a 2 bolt main.

I am sure GM spent millions of dollars on how much power a 2 bolt block will take and a 4 bolt block will take.

Here is a link to of a guy on this forum that tried to out engineer GM and ened up with a broken cap and I am sure he was not even close to 500 horse and again if he wooud have used a 4 bolt block to begin with he would not have had pull the engine and put 4 bolt caps on it.
http://forums.corvetteforum.com/c4-t...ps-1992-a.html

This guy found out the hard way his 2 bolt was not working for him.

http://www.ls1tech.com/forums/advanc...ever-seen.html

This guy just pulled his engine down and found the bearings a mess becaus of the caps moving aound and this engine was only had a 3.480 stroke.
http://www.camaros.net/forums/showthread.php?t=170780

Here is a long l link but a lot of good info in it
http://www.chevelles.com/forums/showthread.php?t=38173

Golens engines builds a lot of stroke engines using the Lt1 block and they install 4 bolt caps on their builds because.

We build alot of 375 horse 2 barrel circle track engines and I can tell you this 2 bolt mains don't work there either and we have seen to many guys try it and it does not work.

It doesn't matter if it circle track, street and strip, marine if its 400 horse its 400 horse.

Most guys that argue this have only built one engine that has worked for them and most machine shops don't have the ability to put good caps on.

If 2 bolts were good for 500 horse it would sure save me a lot of time int the shop over the years.

Pete K

[QUOTE=BLOCKMAN;1572542906]Not to start a flame here but I have built a lot of engines over the years and have never seen a 500 horse 2 bolt work QUOTE]

Educate me. What is the definition of work?
Caps not walking?
Or crankshaft cannot stay in the block?

I have been spraying the nuts off my 383 motor for 10 years, until I lost ring seal and needed a refresh. It ran high 10's @ 129 in a 3400 pound vette, so I assume it was making 500+ horsepower.

After running it for so long, I can say that I did see slight evidence of cap walk, and bearings good enough to reuse, if I were silly enough to do so.
I also detonated the **** out of it more than a couple of times too, so I am presuming that could very well have contributed to some walk also.

Anyhow, looking to learn. Was I shyt lucky all these years?

STL94LT1

Brettmc

Pete- What do you think of the ported stock heads that AI peddles?

AI LT1