GREGGPENN

How interchangeable are the intakes for L98's?

I know 85-88 had 9th injector. 89-91 did not. I think 90-91 have a mount for MAP and an extra nipple on the plenum. I don't know differences of earlier plenums to mine (mine is 1989).

This info will be helpful if/when I sell my intake. Also, if I consider used parts originally for other years.

Will 85-88 bases fit later years (after use of alum heads)? For example, if I found a deal on one honed/plated/polished....

To use 9th injector models, I'm thinking I just need a plug. Use of later years would require non-use of plenum hole/nipple....

Thanks
Gregg

TA

Here's a decent link that shows the changes of various TPI parts over the years

http://www.hotrodlane.cc/PDFFILES/TPIStory.pdf

GREGGPENN

Link

Pics and lots of explanation!

Thanks!
gp

P.S. Looks like a bad idea to use older manifolds on alum heads. Rear passage added for cooling heads.

ramiles

The idle air passages are different by the years - the early years had a special passage in the plenum and a matching idle air from the throttle body. Later year throttle bodies dumped in directly to the main plenum. I learned this the hard way.

GREGGPENN

After studying the link above, there seems to be a "water passage" built into the intake manifold for alum heads. But, I can't quite decide where it is.

Is it the fitting that screws into the manifold immediate behind where the EGR tube enters from the header?

Is there any risk in putting on a aftermarket manifold that doesn't provide this function? The purpose is stated as cooling "hotspots".

Thanks!
Gregg

(Some examples of aftermarket bases include: Accel 74197, TPIS Big Mouth, Edelbrock 3????, HSR, MiniRam, FIRST, etc.... Do we know which have this option?)

65Z01

The water port is near the EGR tube port on the RH side rear of the base; a thin pipe runs over from a "T" in one of the heater hoses.

BTW, very nice info source TA...