Can I use Aluminum heads with speed pro pistons

[whiteThunder]

i have a 3.4, bored .030 over, with speed pro pistons, and was wondering if i could do the aluminum head swap with it, or do i need the grand am pistons? can anyone tell me the difference between the two pistons. i know about all the other modifications needed, but am only asking about the pistons. thanks.

[black34v6]

well id be the best one to tell you. i dunno anyone else that has done the head swap. the issue isnt with the makeup of the pistons, but with the design of them.

if you bought those pistons to use with the iron heads and have 9.0:1 or greater compression then with the aluminum heads it will jump to 14.28:1 or greater.

if you bought those pistons to use with the iron heads and have less than 9.0:1 compression, then it really depends on the size of the dish in the piston. pistons for the 3400 engine have a larger dish than the 3.4L RWD.

do you have specs on them? or can you find out?

[StudlyCamaro]

you provide the CC of the dish in the piston, and we will let you know if they will work or not without a hell of a lot of tuning

[whiteThunder]

the piston part # is h684cp.75 - speed pro hypereutectic. Thanks guys!

[StudlyCamaro]

Originally posted by StudlyCamaro:
you provide the CC of the dish in the piston, and we will let you know if they will work or not without a hell of a lot of tuning

... a part number dosent tell me anything, i need the volume of the dish in the piston

[whiteThunder]

This is all the info i could get off them:
Piston Hypereutectic 92.75mm bore 1-1.2mm, 1-1.5mm, 1-4.0mm rings Dome Top Each does that help any?

[Mr. Merk]

you need to order pistons for a grand am, for whatever compression ratio you want, stock GA pistons would put you at 9.6:1

but as with anything you can get custom pistons if you want lower or higher compression

but you cannot use the pistons you already have

[whiteThunder]

what compression would the pistons i have now give me with the aluminum heads? Why do the aluminum heads up the compression so much as opposed to the iron ones? I beleive that i have 10.7:1 compression now, i couldn't do like 12:1, what would happen if i did? It's not a daily driver

[Mr. Merk]

stock 3.4s are 9:1, by simply swapping aluminum heads it increases to 14.??:1

so starting with 10.7:1, god only knows how much that would be impossible, you need different pistons for the headswap

[StudlyCamaro]

Originally posted by whiteThunder:
what compression would the pistons i have now give me with the aluminum heads?

you still havnt told us the CC of the dish in the pistons, although if you are saying that you have 10.7:1 compression with these pistons then im pretty darn sure that you dont have a dish at all (note i havnt done any math on this one, just a gut feeling)

Originally posted by whiteThunder:
Why do the aluminum heads up the compression so much as opposed to the iron ones?

the combustion chamber of the 3X00 heads is 28cc, wheras the 3.4L heads are 54cc (IIRC)

Originally posted by whiteThunder:
I beleive that i have 10.7:1 compression now, i couldn't do like 12:1, what would happen if i did? It's not a daily driver

if you have 10.7:1 compression with the iron heads i would expect the CR to be way above 14:1 (again no math, just a guestimate) that would require some hella tuning (none readily available short of a stand alone setup) and a cam designed for that high of compression, and race gas