I'd reckon you'd start knocking before gasket goes?

I thought speedway regs were 10.5:1 strict?

Can you run e85?

yeah i'd be more worried about damaging other parts of the engine before the gasket goes...maybe just run 14:1 and tell us which goes first. the headgasket or the pistons

there are much better and safer ways of increasing the engine power

Hi, i run 12.5:1 but with injection and a very good tune. But a standard head gasket seems ok with it.

cant use e85. what elese can i do PIGDOG?.

havent blown many gaskets or knocked pistons rally1200

whats ernie (bige) number?

12.5 on 98 octane? sounds high!

no one will have a definite answer as reliability is very difficult to measure/define

i though 10.5 was a general rule of thumb max comp for reliable motor, maybe injection allows it to be a little higher

letting us know what gear you have and what you are using it for helps us determine what is good for that situation, or what you could do instead, also an idea of if your willing to put money in to it

if its just a knock about i say turbo it!

as i said its for speedway and its got a 14 head with dual outlet exhaust with flatops and carby.

Several new cars have 11.5 and run on pump gasoline. So 98 octane should go even higher.

You might be thinking GM or Ford engine. Aluminum head engines can generally go higher compression since they uniformly cool better than cast iron heads.

I think he means this is a junior speedway engine.

Wind it up till she goes bang and that'll be your limit.

Well the rule with junior sedans is - no more than 60 thou off the head. Clearly some of those compettitors are shaving more off if they are reaching over 10.5:1 So Clyons8, what more can he do to increase compression?