I was just wondering what Kind of Mods I would have to do to get 300 - 400hp from my stock L48. Is it worth it? Maybe I should just buy a crate motor.

Greetings Dave from Dave,

This can be debated for weeks and you may never get the answer your looking for. This is my suggestion, go with a crate engine. If you have the original engine and want to preserve it, this will give you time to do it as you have the funds and you will still be driving your vett. Also, with a crate you have a warrenty, I know I am not the only one who has ever built a engine, taken my time checked everthing and have it go south very early. With a crate you also can get the HP your looking for or can afford. Maybe think about getiing less HP, better milage, then putting alittle NOS in, that will give you the added boost when you need it, Iknow I'll probally get flamed for that also, but its my .02

Thanks,
Dave
Mr69vett

Thanks Dave, I sorta had the same ideas. I think a ZZ4 would probably do the job nicely

A crate engine with a warranty is the way to go !

When comparing HP numbers a crate motor is Fly Wheel Hp and your car is rated as rear wheel Hp everything I have read says about 15 to20% difference. The mid 70"s L48 and L82 engins were under rated to make the feds happy durring the gas crunch. Prices I have got from a good local proformance engine shop were in the 3 to 4 thousand range to rebuild and blueprint my L48 to about 350 very driveable flywheel HP. A Vette is always worth more with a matching # motor.

Ed

So... If you don't have the funds for a crate engine or a rebuild, what will
' bolt on ' mods get you? ie. intake and heads.

All internal cumbustion engines are basically air pumps . The addition of good cylinder heads,intake manifold, and appropriate camshaft wil give the desired results !

G

If you don't have the funds for a crate motor or a Pro Rebuild then you most likely don't have the cash to fix it if you blow it up. Seeing that this is a C3 board you are dealing with a 25 to 30 year old motor so you shouldn't get too carried away. Look at a good Pro Valve Job a Performer Manifold a good mild cam and headers. Even at that you do not want to turn an engine that old that has not had the bottom end gone through by a Pro that builds race motors over 5,000 RPM very often . The Mod's I mentioned should run about $1,000. If that is still to high and you car runs good your best bet is to leave it along and enjoy it.

Ed

Hey, this summer I plan to build up my L48 as well. The current engine is a non-matching numbers engine and is a rebuild from Jasper engines with less than 8,000 miles on it. As I think back at the shape of my original engine, it would have been very unwise to do some more power mods because it wouldn't have lasted long. But this summer I'm thinking about adding headers (probably Dynomax), new heads (probably 64cc to raise compression a little), I'd also like to look into converting to 1.6 rockers, and a new cam (looking at the Comp XE-262). Using Desktop Dyno 2000 (I know its not completely accurate), it estimates HP to be up around 350. Whatever it ends up being, it'll be better than stock!!!

I just sold the perfect engine for you. it was a brand new, never started 93 LT-1. My son worked in Detroit for Ford motor co for two years, and he had some contacts, and bought this engine. Like i said, Brand new, never run!! Sure would do what you want...
Of course, it would not be cheap. Sorry!!!
Good luck with your upgrade.