Intake manifold problems

[samsterman99]

So I converted to TBI from my stock 1986 carb, I left the stock manifold on there and just bought an adapter plate cause of the different center bolts on the head with the carb engine.
I got the adapter and it was for the front mount ( the center and rear mounts make it so I can not get my throttle and TV cable angles to work properly)
THe problem is my stock manifold looks like this:

And I now have the tbi feeding into the small holes from the q-jet, and I see that i am making a HUGE bottleneck at that point. So I wanted to cut out the center of the stock manifold and open it up so I have enough flow and it looks like this :

I have a 1987 TBI manifold, but heard I can not make it fit on my old style heads.
Also this is my DD, and I can not have it down for more than a weekend at the moment, I am in the process of selling my old car and picking up a new DD.
Any suggestions on how to proceed?

 

[Kain]

there is a way to make it fit google it or search youtube
i think you drill the 2 center holes to make it fit

 

[496truck]

IIRC the perimiter bolt heads and the early center bolt TBI heads were basically the same. Intake runners, intake bolt pattern and angle were the same. Why not just get the proper manifold? Cheap, easy and everything will work as designed.

Someone correct me if I'm wrong....

 

[samsterman99]

I have the proper 1987 TBI manifold, what scares me is that I would need an angled washer or spacer to make the entire flat edge of the bolt hit the manifold after I installed it.
Assuming that I got the bolts lined up, everything else should be ok? Dizzy, water ports, ect.?

 

[496truck]

It sounds like you have an intake for Vortec heads, not the early TBI (like the 87). The Vortec heads used a different bolt angle and I think it was 4 bolts per side as opposed to 6 per side like the standard older stuff. My 87 has center bolt heads but the older style intake bolt pattern.

Post up a pic of the intake you have....

 

[4xcrazy]

not all of them, my '89 TBI has the different center bolt holes, it's not vortec...

 

[496truck]

Weird. So, what is different then?

 

[Chevy305]

Just the center intake bolts were straight up and down on all TBI motors, all previous carb motors had all angled bolts all the way around.

You can take your TBI intake and drill out the middle mounting holes so that the bolts fit. Just hold the gasket up to it and use the bolt holes to align the drill.

 

[Stomis]

Angle the holes on the 87 manifold you have and buy some washers. Trying to make your qjet manifold work is gonna be hack. Everything on the 87 manifold will work find just change the center bolts.

 

[496truck]

Just the center intake bolts were straight up and down on all TBI motors, all previous carb motors had all angled bolts all the way around.

You can take your TBI intake and drill out the middle mounting holes so that the bolts fit. Just hold the gasket up to it and use the bolt holes to align the drill.

That's good to know. I just learned something new today.

And all this time I've never even thought to just open my hood and take a closer look...

 

[samsterman99]

Well I started drilling, and drilling, and I still need to remove more material. A lot more than I anticipated to get the bolts in the right direction. I will take some pictures when I finishe it up, sadly this may take me another day

 

[Chevy305]

That's good to know. I just learned something new today.

And all this time I've never even thought to just open my hood and take a closer look...

I should add that on the vortec motors, all the bolts are straight up and down.

 

[496truck]

I should add that on the vortec motors, all the bolts are straight up and down.

Yes, that I knew. Just thought nothing had changed up until then.