ported manifolds to non ported heads

[TazMan]

If I bolt ported manifolds to non ported heads will I still see any gains?

[SappySE107]

Depends on who ports them.

[latemodelnewbee]

There will be alot turbulence where there manifold meets the head. Power gains will minimal until your port match the heads

[SappySE107]

Well, yes and no. Like I said, it depends. I have flow tested stock heads with various manifolds so I know you can port the lower and improve flow without having to port the head. Porting the head will improve it more, but the turbulence issue was different than what I thought going into it.

[latemodelnewbee]

Well i'm used to old muscle where the factory intakes didn't match up with the heads very well, i have to be a good amount porting just to match up everything. I have noticed that this late model stuff matches up very well, to bad they didn't do that back in the day

[IanSzgatti]

i can only say that a larger TB, porterd upper plenum, and ported lower manifold, short ram, and exhaust revealed itself to me. It's nothing spectacular or anything, but it's noticable, and sounds good. If anything it gets you out of the house.

[TazMan]

Thanks for the replies. I got the manifolds used so I'm not 100% sure who ported them but I think it was RSM. I have the manifolds, stock 3400 heads, and a TCE 65MM TB. I was thinking of bolting on the manifolds and TB for now, gasket matching the heads in my free time, and putting the heads on when the weather gets warmer. I already have an extra gasket set that I got for free, but wasn't gonna use cause I wanted to use the severe duty, so I really don't have to buy anything. I was just wondering if the gains would be worth doing the work twice.

[IsaacHayes]

Do it all at once.... Just get to work on it now if you are anxious!

[TazMan]

Do it all at once.... Just get to work on it now if you are anxious!

Right now money is a little tight and I don't have the cash for the porting tools, head gaskets, and head bolts. in a couple of months things will be much better and I will be able to start working on the heads. Since I already have everything to bolt on the manifolds, and I am getting anxious, I thought I'd put them on for now, but if it's not really gonna make much of a difference, I'll just wait.

[IsaacHayes]

3x00 intakes won't bolt up to a 92 3.1mpfi..... Gotta have the heads too..

[TazMan]

3x00 intakes won't bolt up to a 92 3.1mpfi..... Gotta have the heads too..

Oh yeah, I don't have the GP anymore. My bad. I have to update my car info. I got rid of the 92 GP and bought a 99 Grand Am.

[3XTurboAgain]

Sorry this is off topic, Latemodelnewbee, your Jeep has a stock chevy 400 trans? Am i reading that right?

[latemodelnewbee]

Yup in the 70's jeeps with towing packages and/or 401 got the GM turbo 400 with a unique bell housing that bolts up to the AMC V8 or a small block chrysler with out any modifcation. I have a spare jeep turbo 400 and a regular 400 I'll take pics and try to post them here

[IanSzgatti]

ultimately this makes me wonder what is the maximum flow your valves can achieve, compared to what they are performing at right now.