Alright, I was under the impression that if I decided to stick with the 87 GN heads I have now that I would lose my A/C but I talked to John from Johnsperformance today and he said I am gonna have a hell of a time trying to route my exhaust if I use the 87 GN Heads instead of the TTA heads. I am using the H&R Poly Mounts so I know that will give me a lot of clearance with my downpipe but does anyone know anything about the clearance issues with TTA Heads vs. 87 Iron Heads? I have no problem losing my A/C (it doesn't work anyways). Just need some more personal experience opinions here. I can have custom headers and other pipes made but I just have to make sure I am not gonna be sawing away at my engine bay or frame to get stuff to fit. Thanks
89 TTA Heads and 87 GN Swap
- Thread starter 91Bird305
- Start date
The TTA had special headers to fit the car, and the heads. If you had the TTA headers, you would have to modify them to fit the heads. Or if you have the GN headers, you will have to modify them to fit the car. Either would work, but I have no idea which would be less work and less $$.
Hey I'm confused, so forgive me. You are putting TTA heads into an 87GN? If so, IMHO that's not the optimal use of time and money. You'd be way better with stock ported irons, Champion ported irons or GN1's and the stock Buick headers (which you could find cheap if you did not have them).
If it's TR heads on a TTA, John P is right of course. Again, not sure why you'd want to do this. The TTA heads while unique are not rare. Many TTA people have gotten FWD heads from the boneyard, ported them and built them up. Is the issue that you do not have any TTA headers?
Sorry - not being a wise-azz or antagonistic, just confused!
If it's TR heads on a TTA, John P is right of course. Again, not sure why you'd want to do this. The TTA heads while unique are not rare. Many TTA people have gotten FWD heads from the boneyard, ported them and built them up. Is the issue that you do not have any TTA headers?
Sorry - not being a wise-azz or antagonistic, just confused!
No, its an 87 GN engine with 87 GN iron heads. I hear all you lose is the A/C to get them to fit but some people have been telling me I won't be able to route any of my exhaust if I go with the GN heads and to go with the 89 TTA heads instead. If all I lose is the a/c then its no big deal.
The HR stuff will help with issues related to "vertical" movement and spacing but I think Beatby6 means the issue with the downpipe with be space clearance between the motor, shock tower because of the Buick heads and headers sticking out further.
FWIW, Buick people had the same problems when using ATR headers. Some downpipes did not clear them without "influence"
FWIW, Buick people had the same problems when using ATR headers. Some downpipes did not clear them without "influence"
Eric - I'm not the expert here, but your header builder would have to give you an idea of how far those headers will come out, then you would have to know how much room you will have. Then you have the downpipe issue: find a stock replacement (ATR if they still make one) or look for an ATR 3" pipe....which may not fit on the headers. I'll bet the header builder will have to measure and build a custom downpipe.
I think you really want to hook up with either Steve Kaminski who has done a number of swaps into F-Bodies or Dan McDonald. I know Dan's sig on this forum and turbobuicks is "grumpy".
Again, the other alternative is get the FWD heads and look hard for a set of TTA headers. How much $ will the custom ones cost?
I think you really want to hook up with either Steve Kaminski who has done a number of swaps into F-Bodies or Dan McDonald. I know Dan's sig on this forum and turbobuicks is "grumpy".
Again, the other alternative is get the FWD heads and look hard for a set of TTA headers. How much $ will the custom ones cost?
I've talked to grumpy about parts before on the "other" site but not about my swap. I will have to get a hold of him on there and see what he has to say.
I am not sure how much the custom headers will cost me just yet. I am thinkin, either way i am gonna have to have custom headers made since 89 TTA headers are $$$ and hard to find and then there is the clearance problem with the 87 Gn heads and the downpipe. Decisions decsions...
I have heard that stainless custom headers cost at least $800 and probably over $1K. I don't for sure, but I know Dan paid a few bucks to get his done for his stage motor.
If you are paying that much for headers, you should look for a TTA set. I know where to find one set.
If you are paying that much for headers, you should look for a TTA set. I know where to find one set.
Don't the passenger sides on the tta's and gn's headers prone to cracking? I always see them for sale and then "passenger side welded"
And I already have the 87 GN heads ported and polished so its kind of a hassle to now go with the 89 TTA heads but if I don't have a choice then I will do it.
And I already have the 87 GN heads ported and polished so its kind of a hassle to now go with the 89 TTA heads but if I don't have a choice then I will do it.
The option of using the TTA heads (same as some FWD heads) is not as easy as it sounds, since the combustion chambers are smaller. The TTA has special pistons, with a bigger dish than the turbo Regal engines. It may be possible to go with thicker head gaskets, and get similar compression, but that could create other problems. Should be easier to modify headers to fit, either mod the TTA headers to fit the engine, or the Regal headers to fit the F body. Either would be cheaper than finding special pistons, and would let you keep your ported heads. By the way, the drivers side header is more prone to cracks on the Regals, don't know about the TTA....
FWIW.....
I have TTA heads over non-TTA pistons and it doesn't really raise the compression that much like people have been told. The engine builder I used does it all the time. In fact, he said he often gets "TTA blocks" that really weren't TTA blocks with TTA pistons and the owners never knew it. Of course these are not pristine original TTA's where the motor was never pulled. But... I did change the pistons, so I agree with Ormand.... and I don't have all the dirty details on the rebuild with me.
As mentioned the TR's tend to crack on the driver side, but a correctly repaired set will work just fine. Also, you can find them (realtively) cheap.
I have TTA heads over non-TTA pistons and it doesn't really raise the compression that much like people have been told. The engine builder I used does it all the time. In fact, he said he often gets "TTA blocks" that really weren't TTA blocks with TTA pistons and the owners never knew it. Of course these are not pristine original TTA's where the motor was never pulled. But... I did change the pistons, so I agree with Ormand.... and I don't have all the dirty details on the rebuild with me.
As mentioned the TR's tend to crack on the driver side, but a correctly repaired set will work just fine. Also, you can find them (realtively) cheap.
I've personally got a set of the FWD heads now and the RWD heads as well, one thing I noticed that's of personal interest to me is the fact that the runners on the FWD heads are a great deal shorter, which on conventional engine logic would move the power band down, at least a little. Since it's a swap I'm not too worried about fabbing, it's not exactly like I can avoid it honestly. The other thing is that it'd make it easier to polish the runners and such. The chambers do appear smaller visually, I wish I had a burrett so I could tell how much before i finalize my choice of heads and get on with it.
