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Old 04-24-2001   #1
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406 in GTA

I am putting a 406 sbc in my 88 gta. It was originally a 350 car I am keeping the fuel injection and 700R4 (at least temporarily) and am wondering if anyone else is doing, or has done a similar thing.

I don't have any questions to ask about it as I have pretty well figured a lot of other things out, and the performance should be great. This is a stock bottom end 406 (.30 over 400) with untouched 1970 400 heads, simply bolting on an edelbrock hi flo tpi base and the rest of the TPI system.

There has been talk about installing a 400 pontiac and a big block chevy...why not just install a stroker sbc? Same external block dimensions and is a bolt in deal. Lots of fabrication is required for a pontiac engine. The BBC has clearance problems with the a/c box and good luck with header clearence with the steering box. Sure, the accessories bolt up, for the most part, but a similar amount of power can be made from a large cube sbc. Speedomotive makes a 434 all forged rotating assembly for like $1600. Finding and building a BBC is a lot more than a similarly equipped SBC.

The question: Why not just do this? I am interested to see what other GTA owners think. Another option would be to simply bolt-on a supercharger with a few mods.

Just looking for other opinions here.

TIA for the responses,

Adam Stendahl
'84 T/A, 88 GTA
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Old 04-24-2001   #2
Multi-Vehicle Member
Join Date: Oct 2001
Location: Near Tulsa, OK
Posts: 267


Sounds like an interesting project. The only concern I would have is the bolt pattern from the TPI base not fitting the 1970 heads. You may already have this taken care of with the aftermarket intake. The bolt holes are in the same place they are just tapped at different angles. There is an aftermarket adaptor kit that eliminates this problem. Also, be sure your head gaskets have the steam hole drilled out between the center cylinder bores. This is the cause of the ever popular "400's always overheat" statement.
Good luck and keep us posted.
Has-been GTA Owner.Brent
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Old 05-25-2001   #3
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sounds good to me...i'm ditching my 350 as well..but i'm going in the opposite direction...i'm going smaller....transplanting a GN/TTA drivetrain
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