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HotRodr56
01-19-2005, 09:22 PM
I have rebuilt the port side engine for my Z33 and I'm just waiting for warmer weather to clean, repaint the bilge, and reinstall the engine. My question concerns what octane gas I should be running. The engines are/were originally 454 mags. The newly rebuilt is for sure now. Forged pistons with a small dome, 8.75 compression with 118cc chamber 990 rectangle port heads. Stock exhaust, stock 4 barrel, Crane 278 cam. Will this run on 87 with no problems or should I move up the octane rating?
Thanks

Mr X
01-19-2005, 09:45 PM
stay within 33-34 total advance and you should be OK

Donzigo
01-19-2005, 10:03 PM
I have a Z-33 (1989), with 454's in it. I had run 87 octane for the first year and for the last two, I've run 93 octane. (Ted, Cigarette SS, Oneil's has it for the price of 87). It may be my imagination; but, I think the engines run better because of the higher octane and I've been told there are good additives in the 93 fuel, not sure about that. I haven't had a hard start, hesitation, etc. etc. since I started to use it.

IMHO it's 93 for my money...........your call, though.

David Ochs
01-20-2005, 08:46 AM
I'm probably as much to blame as anyone in thinking that we get what we pay for. But the fact is that if the compression of the engine doesn't warrant a slower burning fuel, you're throwing your money away.

mjpcowboy
01-20-2005, 12:28 PM
I have 500 EFI's and some people with a lot more knowledge than me about fuel related issues have told me to burn 87. They have indicated you gain nothing unless you get up into really high HP motors.

HotRodr56
01-21-2005, 05:55 PM
Thanks for the answers guys. I may try a tank of 93 to see if I can tell a difference but if nothing major happens (like +5mph) I will probably stick with 87. Just wanted to make sure I didn't hurt the engines.