intake manifold gasket
10-31-2016, 12:08 PM
#1
intake manifold gasket
Hey guys, this topic has come up many times and I cannot find any answer in the archieves dealing with which intake gasket to use on my aluminum head 87 corvette with the L98 TPI. I have read about guys using the blocked off rear water passage gasket.... fel pro number MS 93318 as the oem did with aluminum heads ......OR use the cast head gasket with the open water port and do away with the little bleed off line. Also the discussion dealing with head gaskets, people favor the fel pro gasket number 1003..
Hope someone can put this confusion to rest as I am sure other guys out there are pondering the same question.. and cannot find a answer..
Hope someone can put this confusion to rest as I am sure other guys out there are pondering the same question.. and cannot find a answer..
11-01-2016, 02:41 AM
#2
Race Director
The general rule is that the engines that have the "steam pipe" use the gaskets with the small holes in the rear water passages. That would apply to all '86 to '91 engines.
11-01-2016, 07:37 AM
#3
FWIW - on my aluminum head 90, I replaced the OE style gaskets (rear restrictors) with the iron head - open rear port type style gaskets (1985 design). did this for a number of reasons. most significant, it seems that AL head L98's tend to blow head gaskets at either #7 or #8 cylinders - same location as the restrictors. I may be full of it, but I can't fully understand why the general wanted to slow down coolant flow around those cylinders. in addition, the general incorporated a steam tube to the right-rear side of the intake, connected to the restricted manifold cavity - "STEAM" 
. just the word "steam" didn't give me a warm fuzzy. anyway, i'm running around 10K miles on the 90 with the open port gaskets - temps seem normal, and that's with the hot summer temps here in florida. i'm not experiencing any issues at this point. I seem to recall, there are a number of us that have made the switch. your car, your call. just my 2-cents. 
edit: BTW, I did keep the OE configuration on the steam tube, and probably not significant, but running a 180° stat.
. just the word "steam" didn't give me a warm fuzzy. anyway, i'm running around 10K miles on the 90 with the open port gaskets - temps seem normal, and that's with the hot summer temps here in florida. i'm not experiencing any issues at this point. I seem to recall, there are a number of us that have made the switch. your car, your call. just my 2-cents. edit: BTW, I did keep the OE configuration on the steam tube, and probably not significant, but running a 180° stat.
Last edited by Joe C; 11-01-2016 at 07:55 AM.
11-02-2016, 02:31 AM
#4
Race Director
The restricted rear coolant intake manifold passage forces the coolant to flow forward through the heads toward the thermostat and top (return) radiator hose.
11-02-2016, 09:22 PM
#5
Le Mans Master
I have been running the rear restrictor intake gaskets for 6 years without the rear vent hose on my 89 and never had a problem..It looks to me like either way will work...WW