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Discussion Starter #1
Im looking for some thoughts on putting vortec heads on my 1987 Pontiac Firebird 5.7 tpi. After looking around I found that I wouldn't be able to run the stock intake manifold because of the vortec bolts being different from the current swirlport heads. I couldn't find a conversion for under $650 usd, I'm wondering if there's any way I can make this work or just scrap the idea. Any suggestions would help!
 

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You can drill and tap the heads for the old style intake 12- bolt pattern, this was done a lot back when Vortec heads were new to the scene in 1996 and carbureted peformance Vortec bolt pattern intakes weren't even available yet.

Do a search on vortec head converted to conventional SBC bolt pattern and you'll find a bunch of info on it.

Needs to be done carefully, as some of the end bolts go into water and a couple have a rather shallow flange thickness so you need to not be ham-handed when tightening the intake bolts or you can strip them. Helicoiling all bolt positions helps with strength on the thinner head intake flange to prevent stripping.

In your specific case, you'll have those 4 center intake bolts with that odd angle, but that is the only difference to deal with versus just the standard old bolt pattern. Just requires a second set-up in the mill or drill press for those 4 on the odd angle..

Several of the aftermarket Vortec bolt pattern heads also come with the old style pattern, having both conventional and Vortec pattern on the same head, but I don't know of any with the 4 angled special TPI bolt pattern.
 

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A non-Vortec intake may have sealing issues at the top of the runners, with racing engines we used to just run a generous bead of grey RTV at the top of each runner, but that may not hold up for street use.
 

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Unless you already have the Vortec heads in hand I would suggest looking at aftermarket head options, the cost of upgrading Vortecs to run more lift combined with the possibility of cracks and rework of the heads to rebuild them makes it almost an even proposition.

I know not what you wanted to hear, not to many good examples left up here in the North and I watch for them religiously.

Welcome to HR.com Bryson!
 

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Edelbrock made a Vortec-pattern lower TPI manifold, but I seem to remember it didn't flow very well. Do some research, they might still be available.
 

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Discussion Starter #6
Thanks for all the suggestions, right now I think I'm going to ask a engine machinist of he could re-tap holes into vortec heads. Headed 3 hours on the highway later tonight to pick up that vortec from Kijiji, thanks for sending that by the way. I'll post more when I find out costs and my plan. I'm hoping that I'll try using the grey gasket maker to seal the intake manifold and maybe I'll just have to re seal it once in a while.
 

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I'm on the side of aftermarket heads they usually come with both the standard and Vortec bolt pattern. Also, be aware there are 2 versions of the standard pattern where 55 to 87 have all intake bolts meeting the head at 90 degrees to the head's intake mating surface and from 87 thru 95 the center 2 bolts on the head change this angle to 72 degrees. Then from 96 to 02 production (L30 and L31 Vortec) the bolts are reduced to 4 per head and meet the intake manifold straight down. Additionally the Vortec heads move the intake port up making it something of a game as to whether a non intake manifold will make and keep a seal above the port.

You need to pull a rocker cover to see what heads are on your engine, typically TPI engines did not have Swirl Port heads these were confined to TBI engines. The TPI engines use a head that is similar but do not have the swirl vane in the valve pocket. These are not too trashy of a head they have about 2/3rds to 3/4qtrs of the chamber features of the Vortec head and overall are similar in capability to the preSMOG closed chamber heads. The Camaro and Firebird also have the L98 option where the head is an aluminum version. So if you haven't look for these things it is worth doing a little inspection of what's there if you haven't looked closely.

The big problem with the TPI engines is the intake, the runners are way too small. Without going through some radical porting of the intake the addition of L31 style heads be they factory or aftermarket will not have much, if any, effect as the lack of intake capacity limits what these heads see in flow well before their capabilities can be turned on. These type changes will lead to a custom chip in the computer as you're moving beyond the factory fuel map, TPI is more flexible than TBI in this regard but is not unlimited in capability.

Bogie
 

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If your going to look at those heads in the link I sent you make sure you stop by my house and pick up my valve spring compressor and dye check kit so you can look for cracks around the valve seats, not worth buying them if they are badly cracked.

At any rate they likely need seats and a valve job so if the cracks are micro sized around the seats they can be reworked, send me a text when you dye them so I can inspect a photo.

FYI about 7-800$ to rework them.
 
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