1st Production LSX454R

The engine advertises 750 HP. That 's a lot of power out of a natural air breathing 454. I do note that it has a 13:1 compression ratio. You aren't going to run this engine on pump gasoline.

My current 70 corvette project has me with a 454 engine. I bought the block and crank many years ago when 454 was a big deal. Today, it looks like you've got to go to 502 to get "respect." But no way can I go 13:1.

The 13:1 compression ratio is way to much. You're going to have to run specialty race gas which is about $10 a gallon. (That's what I paid about 2 years ago for 20 gallons). Even if you can afford it, there's an inconvenience factor.....with a 13:1 engine you can't drive and refuel at long distances since no one has the octane fuel available.
 
68/70Vette said:
The engine advertises 750 HP. That 's a lot of power out of a natural air breathing 454. I do note that it has a 13:1 compression ratio. You aren't going to run this engine on pump gasoline.

My current 70 corvette project has me with a 454 engine. I bought the block and crank many years ago when 454 was a big deal. Today, it looks like you've got to go to 502 to get "respect." But no way can I go 13:1.

The 13:1 compression ratio is way to much. You're going to have to run specialty race gas which is about $10 a gallon. (That's what I paid about 2 years ago for 20 gallons). Even if you can afford it, there's an inconvenience factor.....with a 13:1 engine you can't drive and refuel at long distances since no one has the octane fuel available.
Click to expand...

Actually there are quite a few guys running 13:1 Compression on built LS motors with 93 octane gas. It does require a special camshaft with a special overlap. The other easy way is to set it up to run on E85 that you can get about anywhere.
 
SCCA VETTE said:
Actually there are quite a few guys running 13:1 Compression on built LS motors with 93 octane gas. It does require a special camshaft with a special overlap. The other easy way is to set it up to run on E85 that you can get about anywhere.
Click to expand...

Good to know. I once had a 69 Coupe with a L88 clone in it. The L88 came with a 12.5:1 compression ratio. I had the piston domes machined down to get the compression ratio down to about 11.5:1. With a 3.08:1 rear end gear ratio and the stock L88 cam, I could drive around at low engine rpm with no pinging. I guess a cam with a lot of overlap produces pushes enough air out of the cylinder at low rpm to give an effective low compression ratio. When I bought the engine, you could buy 104 octane gas here. By the time I got it on the road, pump gas octane went down into the 90's. (Max octane here is now 91.) In those days, I added 5 gallons of high octane AV gas to every tank to increase the pump gas octane.

My guess is that E85 will cause a lot of problems with the traditional pot metal Holley carbs and tin plated steel gas tanks and lines. I wish we had the choice of buying 100% gasoline today. (Todays pump gas in Ca is 5% ethanol.)
 
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