delgal

hello all,

small question, what is a preparation of a L48 engine displaying 327 HP to 375 torque? Nervous? does not change much? or is it a small bomb??


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thank you all

enkeivette

What you wrote does not make any sense, neither does that graph. That graph (which was obviously computer generated and not from a real dyno) that shows a 150 gain is BS. It says the gain came from rebuilding the shortblock. The only way to increase hp by rebuilding the shortblock without increasing the stroke, would be to up the compression with different pistons. And no one gains 150hp from more compression. You need different heads and a bigger cam for a 150hp gain, that would be modifying the long block.

redman76

If you are asking what it takes to get 327 HP from an L48, then you would need to rebuild the bottom-end and replace heads, intake manifold and cam. You would also need to upgrade the exhaust system to dual exhaust. There are many options how to accomplish this and you can get some great advice on this forum. There is no easy fix, but many of us are upgrading our motors . . . it just takes time and $$$.

OMF

The bottom end is just fine for that power level (327 HP)...bolt on some vortec heads, a vortec style manifold, and slip in a cam that has a duration @ .050" of 220 or so, and your in business.

NassyVette

redwingvette

That graph is from the article by Corvette Fever. They did a lot of work to the heads, 202 1.6 valves, and replaced the cam with a Crane 272/284 cam as well as replaced the pistons with Keith Black flat-tops.

MotorHead

Everyone seem to be on the same page here, saying the same thing I told in another place:

"You can get some power out of an "L48" but other than the compression ratio of the pistons a new short block ain't gonna give you much of anything. Bumping up the compression ration to 10:1 and putting in a CC 270H cam with stock heads you will barlely feel in the seat of your pants. I wouldn't buy anything from a company that has no idea what they are talking about.

Power comes from the properly matched CR, cam, heads, intake, carb and exhaust the short block has little to do with "

skaping

MotorHead

If the text on the chart said :

"This chart show the power difference between the stock L48 and the new and improved rebuilt L48"

..and told you what they did to the motor to get those numbers it would make sense as it stands it is nonsense

7T1vette

That outfit probably forgot to mention the nitrous tank and system that was added.

MotorHead

I found the original graph

redwingvette

Once again, this graph was taken out of an article that did give all the things that they did to get the extra 150HP. To post it up here without the details does no good for anyone.
If you would like a copy of the full article I would be glad to send it to you. I am not telling you it is great information, just what was done by the magazine Corvette Fever, back in 1996.

MotorHead

Thanks, it's the OP that needs to know the whole story. I got 300HP at the rear wheels out of my "L48", that's about 400 or so HP at the crank so I know what you need

mrvette

Wish I had thought to keep more facts about my old L48 from '72, it was rebuilt by previous owner and it ran fine, clean and mild cam, idle 650 rpm smooth....didn't ping on cheep gas....

so I put a L98 injection on it, and it WOKE UP, I maybe should have stayed with it.....

never did any dyno runs on it, so have no facts, but SOTP says it was a different engine.....