2.8 build help

[91dime]

Im going to build my 2.8 out of my 91 s10, Im going to turbo it. I would like to get about 10 psi forced in, but im not sure what i exactly need to do to the bottom end, I know ill get hypereutectic pistons, arps studs. But my freind is giving me a 3.1 out of a grandprix i think. It has aluminum heads and mpfi. I know i want to use the mpfi, but is there anything else i could use to gain some power. What about the crank and rods? Can i stroke the 2.8 to a 3.1? Will the 3.1 internals stand up to more boost than the 2.8?

[geoffinbc]

Your best option for hte the most power is to use your block but switch to a 3400 top end and MPFI injection. It will take boost and is tunable too.

2.8L or 3.1L cranks are of equal strength.

[91dime]

i didnt think i could swap the heads off a 3400 to a 2.8. Will it raise my compression alot, Im sure i can get pistons to keep it low. What about the bottom end?

[91dime]

will the 3.1 have a roller cam? Will i be able to use it in my 2.8? Ill get the lifter holes machined out to run roller lifters if possible.

[Guest]

Slow down. Do some reading on the 660 and design changes over the years.

No the 3.1 does not have a roller cam. It is a flat tappet. You can't run a roller cam in a genI (The 2.8 you have) block, as the oiling system is not designed for it, nor modifiable to do so.

3400 heads will fit fine on a 2.8 in an S-dime. I ran 3100 heads for two years on my 2.8 block, before I pulled it apart tp upgrade it to the 3400 top end and haven't made it back together yet. I also had a turbo on it.
If you keep the 2.8 crank, you will need to get FWD 2.8L pistons to keep the compression 'lower', at 8.9:1 or so, using FWD head gaskets,using RWD head gaskets will raise it with those pistons to about 9.2:1, which is what I am doing with mine as well, but due to my longer stroke, and a slightly thinner head gasket still it will closer to 9.3:1.
You can use the 3.1 crank in the 2.8 block, as I did the very same thing, and with my overbore it beame a 3.2L

To have MPFI, or rather control it properly, you also have to use an ECM from a FWD car, whihc requires rewiring of the engine controls.

Also when you build a hybrid like you are proposing you will need an external crank trigger, to trigger the DIS coil pack that you will need to run. The FWD intakes do not leave space for the dizzy to be installed.

Custom headers will be needed, both because of the bolt pattern on the heads (port shape as well on the 3400 heads) and due to the turbocharger.

There are also things like throttle cable to worry about and a bunch of small details that will take time and some money here and there to overcome.

[91dime]

Ok , so im stuck with a flat tappet cam. Im going to use an accel gen 7 standalone ecm for the mpfi. So if i use my 2.8 block, and rods, and a 3.1 crank will it be a 3.2? Did you notice a difference with the 3100s over the iron heads? Im not sure i can use the crank trigger and DIS. Im prety sure i will need an hei type system for the accel ecm. I can use the mpfi intake with the stock iron heads right. What about a 2.8 from an 88 camaro, my freind also has one of those , anyhitng i could get off of it that would be benificial?

My main goal is to use the 2.8 block, have mpfi with the accel standalone system, compression around 8.9:1 with a single turbo. If it is possible for me to use the 3.1 crank with either stock iron or aluminum 3100, or 3400 heads and keep the compression low I will use the crank.

Also when you used the 3100 heads what did you do about your acceseries? Did the 2.8 stuff bolt up or dfid you have to change everything to 3100?

Ill do alot more research and reading and try to get a good plan on what I can do . Thanks alot for the help .