[Gmecm] SBC TBI intake to 86 and earlier ???

Wed Jan 10 23:15:21 UTC 2007

Is there anyone who makes a adapter for a TBI to a Quadrajet intake?  Or 
can I use a Quadrajet to Holly converter plate, then use a Holly to TBI 
converter plate and stack 'em like that?

Mike wrote:
> I haven't come across a TBI intake which will bolt on to 86 and 
> earlier engines without modification.
> Tried Edelbrocks website no luck any idea where to find one? P/N
> Are 87-91 heads a direct fit to the 80-86 engine?  or do I have to 
> machine or change out push rods
>
> Mike
>
> ----- Original Message -----
> From: "Beau Blankenship" <ne14roxcj at gmail.com>
> To: <gmecm at diy-efi.org>
> Sent: Wednesday, January 10, 2007 8:01 AM
> Subject: RE: [Gmecm] SBC TBI intake to 86 and earlier ???
>
>
>> Another option (that would look good and perform better) would be an
>> aftermarket manifold from Edel, or Hly. You would have to have the 
>> intake
>> off to drill the holes anyway, so why not just stick a new intake on 
>> there
>> that was designed to fit right. Is it worth the extra cash? How much 
>> is your
>> time worth when you have to chase a vacuum leak or change the intake 
>> gaskets
>> because your "modified" intake is giving you problems.
>>
>> As for the heads, I would try to get some of the EFI heads from 
>> 87&up. 80-86
>> was a big "smog control era". The smog heads weren't good for much. I 
>> use
>> mine for mock-ups. The castings were too thin in the bowl areas for any
>> porting (as if that would help any), and on the "deck" for re-surfacing.
>> Most performance engine builders will warn you away from those "smog"
>> castings. The EFI heads were good for drivability, and can be lightly 
>> ported
>> to improve flow a little bit. For high RPM power, look to the older 
>> stuff.
>> Muscle car heads. Double-humps, etc. There is a great book by David 
>> Vizard
>> about selecting and modifying SBC heads. It's one of the PowerPro Series
>> books. Pick up a copy of that, a die-grinder, some burr-bits, and some
>> polishing stones, and make a weekend of it. Best to do this with some 
>> heads
>> that already need a rebuild, since they will when you get done.
>>
>> Beau
>>
>>
>> -----Original Message-----
>> From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On 
>> Behalf
>> Of jryan at caminofx.org
>> Sent: Wednesday, January 10, 2007 7:36 AM
>> To: gmecm at diy-efi.org
>> Subject: Re: [Gmecm] SBC TBI intake to 86 and earlier ???
>>
>> Redrilling the holes works, but it's ugly.  Without making special
>> washers, you can't get much clamping force on the four center bolts
>> (next to the carburetor/TBI mounting pad).  I drilled a TBI manifold
>> to fit an '84 305, but I wouldn't do it again.  When I got a 350, I
>> got an '87-later-style block and a new TBI manifold and bolted it on.
>>
>> The bolt angle was changed to make it easier to put a wrench on those
>> bolt heads.  It makes a huge difference.
>>
>> TBI high-swirl heads are meant for high fuel economy and low-end
>> torque.  I have them, and I am getting 20 mpg from a 350 in a 3500-lb.
>> car that is not very streamlined.  Mine is a daily driver, though, so
>> low-end torque and fuel economy are more important to me than top-end
>> performance.
>>
>> For what it's worth, I get the same gas mileage from a 350 with TBI
>> high-swirl heads and 9.2:1 static compression as I did from a worn out
>> 305 with 8.6:1 compression.  Same car, same transmission and rear
>> axle, same ECM, only the engine and PROM changed.
>>
>> Quoting Mike <sonoma at shaw.ca>:
>>
>>> Hi
>>>
>>>
>>>
>>> When I installed a throttle body on my friends old Chevy 350 we used
>>>  an adapter.
>>>
>>> I didn't like the look of the adapter so I was going to use the TBI
>>> intake and modify the center bolt holes for my pre-87 engine.
>>>
>>>
>>>
>>> After reading some of the messages here it sounds like there has
>>> been some problems using the TBI intake on the earlier engines.
>>>
>>>
>>>
>>> What is your experience using this intake on an older small block 
>>> chevy??
>>>
>>> Also I was curious which heads are better 80-86 or 87-91 truck heads
>>>  or are they about the same??
>>>
>>>
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>>>
>>
>>
>>
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