Hi. I got a 406 that Im putting together that will have 10.8:1 compression with 70cc edelbrock aluminum heads. Im kinda undesided on the cam. If i go with a hydraulic, I'll go with the 274XE comp or 276 vodoo.

Between these two, would the vodoo cam bleed off more cylinder pressure than the comp 274xe.

I may go with a solid somewhere around 238,240ish @ .050. Would this be OK with pump gas?

I can run 93 octane pump gas and my quench will be .040. And I really dont want to go with a too much bigger cam for fear of overcamming. Should I lower my compression or will it be alright?

Thanks

Also, does anyone have the link for the compression ratio calculator? I looked but I can't find it.

I think you'll have problems with either cam and that CR. Follow the link in my sig for info on CR, cam, and octane.

yes, thats the calculator Im looking for, Thanks pat.

I run 10.63 with 91-93 octane with no problems. My cam is 252@.050 if this helps you at all.

I think you could be ok. My scr is 10.9-1 with aluminum heads and a cam in that neighborhood maybe a bit smaller 23xish? but i have the siamesed cylinders with more coolant around the cylinders. Good luck

Do you think that 276 vodoo cam will bleed off more cylinder pressure? I cant run that DCR program for some reason, but I remember checking my old 383 that had 10.3 compression with the 274xe comp and it could have took a little more compression and been fine. If the lunati bleeds off more cylinder pressure I think it would be fine to go with 10.8:1? Any opinions?

Thanks

Thats kinda dangerous territory with that much compression. You might be able to make it work, but itll be right on the limit and you might not have enough lee-way for it to work under all different types of driving situations. Id probably keep the compression under 10.25:1 or less(10:1 even would be good). I would choose the voodoo camshaft and the 276 would be a good one. With a 400 motor, youd probably want between 3.55-3.73 gears for it as well as a minimum of a 2400 converter. Harold reccomends 3.73 gears and a 2800 converter, but if that reccomendation is based on a 350 engine, than obviously with 50 more cubes in the 400, you could make it work with a slightly milder gear and converter due to the fact that the power will turn on earler. So like I was sayin, count on anything between a 3.55 gear to 3.73 to work as well as a 2400-2800 converter and Id really try to keep the compression safe at 10:1. Thats plenty. The extra .8 additional compression you have now wont make a huge difference in power, but its definitely enough to make a big difference in detonation resistance, so keep it safe and dont worry about losing too much engine power at all.

Ok, I'll go with a -12.5cc dish piston to give me 10.1:1. Id rather not risk it. I was gonna mix in a little 110 octane race gas, but since this is a street car mostly, that could get old.

I am going with a 3000 stall, and the car has 3.42's now, but after I get the 406 in, that will be my next change to 3.73's probably.