Esteemed Corvette enthusiasts, and in particular, engine gurus. Just wondering, although I'm sure my life will continue just fine if no-one answers, or shoots me down for asking a dumb question, but how much HP do you reckon I'd be making with my 74 L48? I rebuilt it pretty much stock except for 0.20 over size flat top pistons, and advanced the cam timing by 2*. I've re-curved the distributor, and timed it as per Lars' instructions. Oh, and it has a 1978 Q-jet for some strange reason. I had the rotating assembly fully balanced as well. I know I'm not going to set the world on fire, but I was after a nice cruiser. Apart from the above mods, everything else is stock.
How much more than the 195hp do you think I might be at?

 

 

Probably safe to say you're getting close to cracking that 200HP barrier.

 

A better measurement would be the torque numbers and when peak torque occurs. With a fresh rebuild and an advanced cam your going to feel a nice rip up to 5000rpm!

But I say around 200hp but close to 300ft lbs of torque at 2400rpm

 

Yeehaa!
You're right about the increased torque. It's great off the line now. Well, way better than it was with a tired engine! Thanks guys!

 

My 1974 L48 with EGR and TCS removed, the distributor recurved, an oversize K&N filter installed, 2 1/2" exhaust pipes, with 160,000 miles, was making about 180 HP at the rear wheels. So maybe 220 at the crank?

 

That's pretty cool. I still have the EGR, no TCS (auto) and the original manifolds with 2" pipes. And an el cheapo 14" air filter.

 

It is easy to get about 230 HP out of a stock 1974 L48 engine on a rebuild project and probably can be done with less than $1500 bucks in parts. Cam, intake and a free flow exhaust will increase HP by about 20 % to 30 % most of the time. It was not until 1975 that they really dropped the Horse Power to 165 HP in the L48 engine than slowly increased it back up to 190 HP in 1981 after introducing emission control systems. You can keep the 2" exhaust system because in the two holes next to transmission probably will not handle much more then a 2.5" pipe. I think the 1974 had dual exhaust and a free flow muffler like Magna Flow, DynaFlow or Flowmaster can give you from a 5% to 10% increase on HP just by upgrading to a louder exhaust system. If you added headers into the mix this will give you the best breathing of the engine and get you closer to 250 HP.

A 1974 Stingray equipped with the L48 195 hp (145 kW) small-block was capable of 0-60 in 6.8 seconds. Information taken from Wikipedia on the L48 engines.

From all my reading and research the 2 Bolt main L48 engine can handle up to about 350 Horse Power and they make a 383 Stroker Kit for this engine that will provide 300 HP after installed. You will not be able to run the RPMs like a 4 Bolt Main L82 engine will but it is entirely possible. A 383 Stroker kit you can expect a rebuild to cost about $3000 Bucks and if you have the money go for it

Before I bought my 1977 Vette a Dude I talked to had a 1976 with all the emission controls removed was attempting to sell a 1976 vette for $9000.00 and he put his on a dyno with paper work to prove it after 383 Stroker Kit that produced 326 HP. I passed it over because I did not want to spend about $2000 bucks investing in emission control systems and tuning it down. It was very tempting and wish I did since this car was almost completly rebuilt. I have spent about $2500 on my 1977 and still have around $1500 more to spend on the suspension to rebuild it and not even close to what was done to this car. But is was worth it My 1977 only has about 44,000 original miles on the car where as the 1976 was over 100,000 miles.

 

Thanks for the info MJ.
Not really chasing HP. Just keen to fine out roughly what I had over stock. Engine is matching numbers except carb, so I don't want to do anything to it. But the next C3........!!
I'm going to keep mine and do small jobs on it until maybe early next year, then sell it and look for something big blockish and chrome bumpery, depending on the market, exchange rate, etc of course!

 

If the "seat of your pants" is happy, don't worry about the HP number...