3.1L heads on a 2.8L

[shark_bait]

I plan on installing 3.1L heads on my 2.8L. Will it mess up the computer? Do I need to change anything else?

[robertisaar]

exactly what are these heads coming off of and going on to?

[shark_bait]

they're goin onto a 89 camaro w/ the 2.8. i dont know where i'll be gettin the heads yet.

[neo71665]

All the fuel injected iron heads are the same so it wont hurt a thing. Unless the 2.8 heads are screwed up you just as well save them and rebuild (port polish and all that good stuff) them for your 3.1.

[robertisaar]

All the fuel injected iron heads are the same so it wont hurt a thing. Unless the 2.8 heads are screwed up you just as well save them and rebuild (port polish and all that good stuff) them for your 3.1.

right: all Iron heads are the same, but he didn't mention anything about using the 3.1 block, just the heads...

shark_bait:if you mean aluminum heads, its been done before since john(forcedfirebird) is using a 3.4(originally iron head) block with either 3400/3500 heads/intakes...

[no_doz]

if you want to use a 3.1 MPFI heads & topend, youll need to change the computer & modify the wiring harness a bit to go from TBI to MPFI.

that is, if the 89 2.8's are TBI, im pretty sure they are but dont quote me on that.

[robertisaar]

that is, if the 89 2.8's are TBI, im pretty sure they are but dont quote me on that.

ahh, but i will... they were MPFI back then as well, no worries there.

[neo71665]

right: all Iron heads are the same, but he didn't mention anything about using the 3.1 block, just the heads...

Right and wrong, The older carbed 60 degree iron heads had smaller valves, but yeah thats why I said all fuel injected iron heads.

He did mention it going into a camaro so I stepped out on a limb and guessed he was building a RWD setup and prolly going the simplest route and not building a hybrid.

[ForcedFirebird]

if you want to use a 3.1 MPFI heads & topend, youll need to change the computer & modify the wiring harness a bit to go from TBI to MPFI.

that is, if the 89 2.8's are TBI, im pretty sure they are but dont quote me on that.

I quoted you for integrity, and sorry, but the 89 2.8 has the same exact top end as a 3.1 - with the exception of the "2.8" badge in the middle of i the UIM The only difference is that the 2.8 used a MAF ECM and the 3.1 got speed density.


And correct, all iron heads are identical after the 85-86 area when GM when to EFI.

[shark_bait]

so if i was planning on putting a low-boost (6psi) centrifugal supercharger, would porting the stock heads help get that extra air in?

[robertisaar]

porting WOULD he beneficial, so long as you don't make the runners too thin and cause the boost to punch through them...

that being said, i wouldn't put boost together with iron heads, but the 3.8 guys do it all the time...

[no_doz]

wow i honestly thought the 2.8 firebirds/camaros were TBI, does this mean the 87+ 2.8 s10s were multi port fuel injected as well? if so thats great news for anyone wanting to do a 2.8 top-swap!

also you may want to check the CR calculator & see what compression you're going to end up with depending on what heads you go with.

either way though, everything ive heard has said to stay away from the iron heads in general if you are going to do a top swap, and you can quote me on that one :P

[robertisaar]

s-10s never got the multi-port setup.

[no_doz]

ah, thats where im getting that bullshit from then, i had one & my friends had a couple of the 2 wheel drive GMC ones from 90-92 & we always thought they were tbi but we never had to work on them so i never took much of a look at the motors.

i never really gave it a second thought but we almost never had to work on them...& thats kickass! lol

[shark_bait]

pretty sure my car is TBI. and i've done a ton of work on that car! finally past the engine after 2-3 years of headache! woohoo!! now for some paint... lol