deity4uu

Hey, guys, I just brought a 75 with a L48 engine. I will be pulling the engine for a rebuild and would like some suggestions for obtaining 300 hp out of my L48. I have a budget of about 2k.

Keesterdog

Put another L48 in there with it. That will put you a little over 300.
Headers and maybe a set of nice used heads and cam.

deity4uu

Any suggestions on cam, heads?

cv67

300 at the crank or 300 at the tire?

Shooting from the hip a set of AFR 180 heads a "256 to 264"" type cam 650cfm carb good dual plane and a set of 1-5/8 headers will get you a real good mannered 350 that will make torque like noones business. Curve distibutor accordingly. Hard to go wrong with combos like that

diehrd

Heads , heads , heads ... Match a cam to them and tighten up the lower end and 300 should be easy as pie ,, U can get a 260hp crate for 1500.00 so 300hp should be easily obtainable with what you have.

And you can do it with vortec cast iron heads believe it or not which are very in-expensive vs the power delivered by them.

deity4uu

300 hp at the tires. What should I do to the block in connection with putting new heads and will my stock automatic transmission, I think it is a th 400, handle the additional HP and torque generated?

78SilverCam

lmao!

If you are looking for 300 hp out of an L48 (like I am) then you need to consider a crate engine vs. heads etc.

If you go with new heads, you are going to need new camshaft and a bunch of other mods as well (it's all connected/related).

The total cost of engine mods will run you close to, if not more than the price of a crate engine. The main difference being your pleasure/frustration of 'building' a 'new' engine.

A lot of people will recommend (for good reason) a ZZ4.

http://www.crateenginedepot.com/ZZ4-...609-P9406.aspx

Hmmm...I can't wait to afford that...

cv67

It shold take it no problem 400s are stout. I enjoy a nice shift kit to firm things up. A converter around 24-2600 would work real good. Youll really enjoy it wihtout rattling your teeth out at lights and fussing with it all the time. Thats for old farts like me.

diehrd

To do that 2k may not cover it.

gbvette62

Put a set of 10.0:1 pistons in it. That's all the factory did.

The base engine in 69 & 70, was the L-48 350, rated at 300 hp. The 71 and later L-48's, are basically the same engine, with 8.5:1 pistons.

Of course, that was gross horsepower, not net.

694speed350

That was at the flywheel also not at the rear wheels.

qwank

Not gonna happen cheap, the only thing you'll reuse is the block and oil pan. Those numbers won't even happen with a stock ZZ4

dpw21562

Edelbrock makes acomplete kit.

lars

Here is a post on an engine I built that put out 300 horsepower at the crank, complete with dyno numbers, and the "recipe" for getting it done. Cost was $3500. Getting 300 at the rear wheels will take about 360 horsepower, which means you'd have to throw another $1500 at it for a good set of heads - that puts you up around $5K.

http://forums.corvetteforum.com/c1-a...o-edition.html

Lars

Grumpy78

Summit Racing has a SBC 383 ci 430 hp for under $3700.

rogman16

Great build and even better video Lars!!

Rogman

kanvasman

not exactly the zz4, but same company, 290 HP all you need is a carb h20 pump & starter. http://www.crateenginedepot.com/350-...10940C944.aspx $2400. Not a bad deal

bluedawg

Afr 180cc, xe256hr. should net you a little over 300 horse at the crank. will also cost a little more than 2k more like 3k but well worth it.

MBC75

I know this does not answer your question but maybe it will help. I have a 1975 L48 and wanted more power just like you. I did a lot of research on building up what I had. In the end I purchased a 383 stroker from Smeding performance I did add some extra upgrades but I got everything I wanted, including piece of mind with a warranty.

deity4uu

Thanks for all your sugestions. MDC75, how uch was your stroker, and did you you have to upgrade your transmission and gears for the additional power?