I posted this up in the General section, but I didn't get very many responses. Maybe you guys can explain to me this setup.

I am installing a 90 TBI unit from a Chevy truck onto my '77 350 in my FJ40.
The guy that modified the 4 middle mounting holes on the TBI manifold told me that I needed the later model intake manifold gasket. The difference being that the rear most ports on the gasket are blocked off. He said that this was due to something being different with the rear-most runners on the TBI manifolds. Well, after picking up the later model gasket I get to looking at the TBI manifold and the runners don't look that different from the Eldebrock performer manifold that I pulled off.
So, did I still need to use the gasket that is made for a '90 TBI intake manifold with the bolcked off rear ports, or do I just need to use a regular intake manifold gasket that has all the ports open?
I am sure that some of you guys have done this same swap, so post up what you know.

on my 1991 TPI motor, the rear coolant passages are blocked(by the gasket and the fact the manifold has no provision for coolant there.)

Why did you choose to use the stock intake? I am starting this same conversion with a tbi from a '89 Blazer and plan on getting a adapter to bolt the tbi to my Eldebrock manifold, light weight and may give a little better performance.

Sorry, I dont have any info about the manifold port question.

Originally posted by t wrecks
Why did you choose to use the stock intake? I am starting this same conversion with a tbi from a '89 Blazer and plan on getting a adapter to bolt the tbi to my Eldebrock manifold, light weight and may give a little better performance.

Sorry, I dont have any info about the manifold port question.

I was going to use an adapter, but after talking to a couple mechanic friends of mine I decided to modify the stock intake. The first reason being that if I was going to use the adapter with the Eldebrock manifold I have, there was a good possiblity that when it was cold here (which is a good part of the year) that my TBI unit could freeze up.
Second reason is that it only cost me $10 to have the four middle mounting holes modified. I figured this was better than spending $40 on an adapter.
Third reason. I have conflicting reports on this one, but some of my buddies told me that it wouldn't run right with the Performer manifold. When I asked people here on the board, they said they were running the adapter with no problems. So, I was wasn't completely sure, I decided to go the safe route

Anybody else have an answer to this?

I installed the intake with the regular gaskets. My manifold (an 88) used the rear coolant ports and fed the heater. My block is a 327, but I did install the TBI heads and the TBI intake.

My stock TBI manifold uses a heater hose port in the rear. It needs to use the not blocked off gasket.

I did not like the low end power from using a holley manifold with a GM adapter to TBI. Mine is much better with the stock manifold.

I have a student trying to turn his Camaro back to TBI after it had a carbed motor dropped in. he is having all kinds of stupid fitment problems with a Painless adapter. It uses the larger rear bores to feed the fuel in and the IAC hits the EGR. We used a second plate to clear the EGR and now he has hood clearance problems. He also now has throttle cable and kick down issues.
Obviously not an issue with a 40, but it illustrates potential problems with adapter plates.

My friend is running the stock 454 tbi set up on his Edelbrock RPM air gap manifold without any problems. It doesn't matter how cold or hot it is. It always starts up and runs great and his motor is putting out over 500HP. It is one wild ride. I would just get the adapter and run it that way.

I did the same conversion on my 73 cruiser last year. I assembled the gaskets just the way they came which was blocked. But were it was blocked had metal plates with a small hole in the center. After putting it together the cruiser would run hot and i thought that those plates were restricting to much water. So i took it all apart again and took out those plates. It made no difference at all in my cooling problem. So all that work was for nothing. I finally found my problem after a shit load of money and time spent. I needed to go to a 5 row radiator, just modified the stock radiator. Prior to going TBI i never had a cooling problem. Currently there are no block off plates in my and i have no issues at all.

oubus, I know this getting off topic but... Whats your plans for eprom tuning? Are you going to leave the PROM stock, burn a modifyed program your self, or have someone else do it? I plan on modifying my chip myself and have spent a lot of time researching how to do it. I am going to have a good time:rolleyes:

Also, what HP is your motor and is the tbi you are going to use stock? I am not sure if the stock tbi will have enough cfm's to feed my motor ( around 290hp ) at WOT. I have heard from different sources that you can use a high pressure fuel pump with a regulator and just turn up the pressure to get as much gas as needed. But this wont allow for more air flow.

Check out thirdgen.com There is a lot of TBI tuning tricks there including making the stock regulator adjustable. Putting in an inline regulator will not help. You need to replace the stock unit or make it adjustable as it is integrated into the injector body.

actually its thirdgen.org

anyways, quick hijack...

will my 88 tpi intake bolt up to my 91 tbi heads?

Originally posted by t wrecks
oubus, I know this getting off topic but... Whats your plans for eprom tuning? Are you going to leave the PROM stock, burn a modifyed program your self, or have someone else do it? I plan on modifying my chip myself and have spent a lot of time researching how to do it. I am going to have a good time:rolleyes:

Also, what HP is your motor and is the tbi you are going to use stock? I am not sure if the stock tbi will have enough cfm's to feed my motor ( around 290hp ) at WOT. I have heard from different sources that you can use a high pressure fuel pump with a regulator and just turn up the pressure to get as much gas as needed. But this wont allow for more air flow.

I am going to have a local guy custom burn me a chip to work with the specs of my engine.
I think that my engine is around 300-320 h.p. I am using the stock TBI unit. I have been told that the stock unit is okay to use up till 375 h.p. I have not verified that, but I am sure that I will find out in the near future.

Or you could use a throttle body and ECM from a 454 with aftermarket injectors. That is what my friend ended up doing cause the LT1 wouldn't feed the motor at anything above 3000 rpm.

can anybody answer my question?

If your TPI intake is anything like my TBI intake, then the only thing you will need to do is modify the four inner-most mounting holes to have the same angle as the rest of the mounting holes. I have never seen a TPI intake off of motor, so I can't tell you for sure weather it is like TBI intake or not. Sorry, I can't be more of a help, but HTH.

Originally posted by Mr McGee
actually its thirdgen.org

anyways, quick hijack...

will my 88 tpi intake bolt up to my 91 tbi heads?

Yes.

[QUOTE]Originally posted by ouibus
[B]

I was going to use an adapter, but after talking to a couple mechanic friends of mine I decided to modify the stock intake. The first reason being that if I was going to use the adapter with the Eldebrock manifold I have, there was a good possiblity that when it was cold here (which is a good part of the year) that my TBI unit could freeze up.
QUOTE]
I have had mine on an adapter on an Edelbrock Torker since last summer, had no problems even on 10 degreee mornings. Money difference worth it to me not to have to swap an intake.
Butch

[QUOTE]Originally posted by ouibus
[B]

I was going to use an adapter, but after talking to a couple mechanic friends of mine I decided to modify the stock intake. The first reason being that if I was going to use the adapter with the Eldebrock manifold I have, there was a good possiblity that when it was cold here (which is a good part of the year) that my TBI unit could freeze up.
QUOTE]
I have had mine on an adapter on an Edelbrock Torker since last summer, had no problems even on 10 degreee mornings. Money difference worth it to me not to have to swap an intake.
Butch

hey, are those heads the same besides the intake bolt pattern? do the trans am ones flow better? any other differences?

Originally posted by Mr McGee
hey, are those heads the same besides the intake bolt pattern? do the trans am ones flow better? any other differences?

AFAIK TBI stock heads are all the same.
Butch

Yes you TPI system will work, and yes the heads are the same. I think 87-95 share the same heads, and the vortec changed that in 96 but I could be mistaken.