mesterious

iTrader: (3)

I have a 406 SBC and im about to get my Cylinder heads (AFR 210) and im going to get the combustion chambered milled like i want them from them my set up is: 249/255dur@.050 624/640 lift 110LSA 106ICL, im looking for 550hp, im in mississippi so weather in summer is from 75-85 in spring and 80-100 in summer and im aprox. 750 feet above water oh yeah and i want 93 octane. If you need anymore info tell me, i would love the help thanks.

ssdeuce74

iTrader: (2)

i've seen 406 with 11-1 runnin 93 but it had alot to do with the cam profile that info i don't know but in general anything under 11-1 should do i have a 406 alot like yours one step up on the cam and have 13.5-1 and its about 625hp with same heads your pretty close

fastgmc53

iTrader: (33)

For today's pump gas I dont trust anything higher that 10-1 for street use on 93 octane with a carb setup..... fuel injection a little higher but that's just me

supermouse4

With aluminum heads, you can run up to 10.5-1 compression. They are much better at transferring heat in comparison to iron heads.

novaflash2002

iTrader: (51)

i ran 11.6:1 with 32 degrees of total timing with a iron headed 406 in wyoming at 4400 feet with 91. main key is to get a nice cold plug, and also make sure all the sharp spots are cleaned up. that is a thick cam so you will need to look at the comprimises as far as more compression or more timing. 11.5:1 should be safe abd give you enuf timing to do some good.

mesterious

iTrader: (3)

well if thats so then i can get my AFR heads without having to pay extra $200+ to get them milled down.. i can buy them with 65cc combustion chambers and get 11.3:1 for regular price. Can you spec me out some spark plugs please? and should i use a 160 degree thermostat?

novaflash2002

iTrader: (51)

ngk has always had a good plug, it will depend on what head you get for the type of plug. br8es are good and same with the tr8s. 160 thermo will work, but honestly i never put one in my car. never had a problem.

SMITHBERG RACING

I've done similar with a 427 SBC Iron head 11:1 and a 406 SBC Aluminum head 11.5:1 both with a fairly hot plug 36 degrees timing on 91 fuel. Both were decent sized solid roller motors. Alot of it has to do with cam design to be able to run higher compression on pump gas.