dslbrnr

Years ago I bought a Bahner jet boat with a 30 over 454 corvette block and I was told it had 13-1 pistons. I was also told to run atleast 100 octane fuel. The guy I bought it from said to use 1 qt. toluene to 10 gals premium fuel, which would make 100 octane. I purchased the toluene from the Shell petroleum plant at $30.00 for five gals. I could also run AV gas 50/50. The motor was said to have approx. 700 HP. On the compression guage it would pump up to 250 PSI.

I ran that motor for 3 years and ran it frequently at 6300 RPM with no problems. I finally had to give it a valve job because one of the valve springs broke (it had double springs) . The block had metal O-rings machined around the bore.

I always set the timing by ear and retarded it if I heard any pinging.
It ran approx. 90 MPH and was a wild ride. I never had any other issues with that motor.

The motor was built by a shop called Wilder Racing in Pomona CA. This was in the early 80's.

I guess it also depends on who built the motor and how you take care of it.

stevesxm

so you took a 700 hp big block at 13 to 1, hand mixed some fuel for it out of whatever you could find on the day, set the timing " by ear and ran it at 6300 revs...

well... assuming that any that is even remotely accurate all you have demonstrated are all of exactly the wrong things you can possibly do with a good piece of hardware..

you are correct in one thing.. it all depends on who is taking care of it...

and i wouldn't let you take care of my lawn mower.

dslbrnr

I won't argue with you because you feel you know it all!!!!! I am just telling you what I bought, what I was told, and my experiences running it!
This was the early 80's and that was how they ran then! The guy that built the motor was well known for winning races!
I didn't say I had the exact specs on the build, but I did say what the compression guage read 250 PSI!!!

Yeah my lawn mower runs great too and it's 17 years old!!!!

bcfountain

kreed

iTrader: (2)

I dont know how guys used to get away with "timing by ear". Especially in a boat with 13 to 1 comp at 6300 RPM????? To me, It just goes to show, sometimes when you just dont give a Sh!t, you get away with murder! The second you start worrying is when thing start going wrong!

PatriYacht

The only way to know what compression these engines have is to do all of the math. My 548's have 10cc dome pistons and my compression worked out to 10.0 to one. I doubt if 22cc dome in a 502 works out to 12 to 1. Probably more like 11 to 1. Still high but workable with a mix of racing gas and 93. It probably needs about 100 octane to live. I'd mix half and half 110 racing gas with 93. Or just change the pistons.

PatriYacht

Ha, Rmbuilder beat me to it. I should've read the whole thread before I opened my mouth. Thanks for the info.