I've got a '91 350 w/87000kms & I've been contemplating between the 2 above mods. I'm looking for some opinions & I'd like to hear some, so tell me what you think would be a better mod & why.
Any & all feedback is appreciated.

 

Either way your going to have to rebuild the motor, so might as well do a supercharged 383.

 

I'm not an expert on charging, but I am working on a 383. If you go with the 383 it'll only be as strong as you make it. Because, technically, boring the engine over and using a longer crankshaft makes it a 383. That would add more punch alone, but using different heads, cams, and all the other stuff will take it further. I'm pretty sure supercharging only requires a few stronger components (mostly in the rotating assembly). The strongest 383s I've read and heard about put between 450 and 500 hp/tq to the flywheel. But supercharging can easily get you 100 or so more hp/tq. So really its a money issue. How much you want to spend, how much labor you want involved, and how much time you want to spend on it, are the big issues.

 

what do you want to do with the car?

 

rebuild the 350, and boost it, look back no more. unless you rebuild it and use a 383 crank.

YOU'll have to get forged everything pretty much.

forged slugs, forged rods at the least, as well as a strong crank. Mine is mitrided 4340, strong stuff, mine will be ready for the 150shot and supercharger i plan on adding. But its just a 350.

At the least you'll be looking at $1000 in parts as i did.
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also notice the engine has 87000km, 54,059miles. HE can run a few lbs of boost for a while...

 

All SBC rods are forged even the stock
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I'd say go with a 383 no matter what. Your going to have to buy new pistons anyway so mihgt as well go 383. Your probably going to need crank work, so go with a cheap 3.75" crank for the same or less money.

The only thing you have to decide is if you really want to go supercharged. It will change your piston selection.

 

well the degree of forging is the difference.

 

No, its the alloy.

 

not exactly, try forgeing one type of steel, say 5140, the same degree 4340 is forged.

5140 doesnt compress(forge) like 4340 does. Which allows to become stronger. Materials in the alloy allow it to forge.

Its like compressing hydrolic fluid, it cant be done, but other fluids with less, well... (forgetting my vocabulary, but ability to compress) can and are the reason they are not used as brake fluid or jack oil.

My grand pa is a metalergist(~sp). well was, he retired....

 

Your not making any sense at all. I think your talking about different crystal and grain structure formation, which has very little to nothing to do with the forging process used to make rods.

I'm a mechanical engineer so....

 

I disagree with you both. '94 and up LT1/4 and L99s use powdered metal rods, not forged...

 

They sure are forged. Its just a different process. Powder metal is used instead of a blank.

 

ok, someone is right here, nto sure if its me, but the strength is guarenteeably different!

Point is,he can build a strong motor cheaply, if he waits for the right deal.

Like a guy building an engine and well, family died, needs all the cahs he can get even its it les then half what he paid...

Thats how i got my rods!

 

Ok..............



A super charged 350 TPI is going to be much quicker then a N/A 383 with TPI sitting on top.