moreyes

I searched several times but i didn't find what i was looking for.
I have a 85 tpi and i was wondering if it can be drilled so it fits the newer style heads. Would having the cold star injector be a problem with the newer style heads or it doesn't make any difference?

Would it be better and cheaper to just buy the newer style manifold?

rgarcia63

What's your goal? Do you want to keep the engine you have, and use the newer style heads? if you're not changing the Engine Control System, (and wiring harness) the Cold Start Injector has to stay. I deleted mine, and used an 89 Corvette MemCal in my 88 ECM. The 85' has a separate MAss Air Flow Sensor control module piggybacked on the ECM, in 86' it was integrated in to the ECM.

I kept the TPI look when I upgraded to a 388 simply because it's mostly for low-end torque, cruising and occasional WOT. If racing was my main objective I'd opt for an LT1 intake conversion, or an Aftermarket TPI, or Twin Turbos, ..etc sorry I'm beginning to drool all over myself.

moreyes

i want to get a 350 but the nicer heads have the 87 and newer pattern which my pre 87 tpi doesnt have. i'm keeping the computer as it is only upgrading the prom. Can it be drilled to fit or do i need a newer tpi?

thirdgen88

If you could get a 350 with aluminum heads, your TPI system will bolt right up.. The corvette aluminum heads stayed with the standard bolt pattern..

91GTABird

You can use your intake on any SBC Gen I heads. They denote the pre 87' heads b/c of the pushrod path. Youll just need to use a Flat tap cam, non-self aligning rockers and check your pushrod length. The only heads your intake will not work with are Vortec (without a SDPC Base), LT1 or LT4 (without machine work), LS1, LS6, or LS2(forget about it).

moreyes

casting (113)s? are you sure of this? They dont have the center bolts?

thirdgen88

Since there seems to be some confusion on this topic here, I will clarify..

There are several differences in the '87-up iron heads.. Yes, they started using self-aligning rocker arms.. But the primary difference pertaining to the intake manifold is that the center pairs of intake-to-head bolts are drilled and tapped at a different angle then pre-'87 cylinder heads.. They are at a 72* angle instead of 90*.. This means that you must modify your '87-up F-body TPI manifold to work on older heads (or, in his case, you would have to modify your '85 TPI manifold in order to mate to the '87-up IRON heads)... Keep in mind that vortec heads are a whole other issue that we don't need to be concerned with here...

Now that that is clear, I will restate that the corvette aluminum heads retained the standard chevy intake bolt angles (all of them at 90*) and your '85 TPI manifold will bolt onto those cylinder heads (even TPI corvette heads after '87)..

Hopefully this cleared some things up..

EDIT: just in case--all of the cases I've cited here have 12 intake-to-head bolts... Only when vortec heads for the Gen I SBC were introduced were the center pairs eliminated ...

moreyes

Ok so the vette with aluminum heads had to come with the pre-87 angled intake right? If they came with Iron heads then they would come with the new intake bolt angle right?

So does this mean that the vettes came with different intakes according the type of heads they had Iron or Aluminum?

pictures would help

rgarcia63

Pictures:
Scroggins Dicky Performance Center TPI High-Flow Vortec Intake Manifold on aluminum FastBurn Heads. The head has raised runners (.240" higher than conventional 23° head) intake ports.
These heads are also drilled and tapped for angle bolts.

GMPP Fast Burn Aluminum Head


Heads and Votec Intake

thirdgen88

... No vettes came with that intake obviously... Yes, the corvettes retained the standard intake bolt angle (and pattern)...

rgarcia63

True on both points, and I know that the Vortecs are excluded here, the pictures were only to show the intake 90° bolts, and the deleted center pair bolts, and the conventional 72° holes (including the center pair) in the head.

thirdgen88

The degree angle of the intake bolts is referenced to the intake manifold mounting surface on the heads... So, vortec heads for example would have the bolts at about 45-50* (but we just call them straight up/down).. The fast burn head that is pictured has the vortec pattern (two pairs of bolts on the four corners of the intake for a total of eight) and the standard intake pattern (twelve 90* bolt holes, no 72* bolt holes on there)...

thirdgen88

Perhaps, as RB83L69 says, a picture might be able to replace all of these words... In the following, consider the black line to be the cylinder head where the intake manifold bolts to..

Red Line: Standard 90* intake bolt

Blue Line: 72* intake bolt as found on '87-up iron heads on the center pairs of intake bolts

Green Line: Vortec intake bolt (straight up and down, or by the degree references here: 45*)..

brianp454

I have a couple intakes for the newer style heads I can trade for on older one. They are bead-blasted and cleaned up real nice. Let me know if you are interested and I can send pics and the actual part numbers.

Rice01

Sorry to revamp an old thread, but I am trying to accomplish the opposite of the OP, I have an '88 TPI intake that I would like to put on some aluminum heads that have the pre87 90* bolt angle, can the intake be machined in some way to make the bolt angles match? is this common place or is there a shop anyone can recommend that I could possibly ship my intake to for this "procedure"?