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I know Army has a thread like this going, but I don't like to hijack threads so I will start a new one.

I am always looking 2 or 3 projects into the future, and since I finished my wheel well saga, I thought it would be fun to pull my tripower setup out of storage and think about what to do with it. I spoke with John at pontiactripower.com and asked him what parts he thought I would need to rebuild the carbs. He said that the parts that he would recommend would depend entirely on my plan for the motor, such as cam choice and heads. Which led me to this...

I have a good magnafluxed 1973 400 block that I was planning on building with a stroker kit from Butler. I also have a set of magged 6X-4 heads. Id like to see 500 torque and 400+HP out of the motor. I am keeping the 4 speed, although I may opt for the M22Z with 2.98 1st gear. My rear is a 3.23 posi 8.5 from a 71 Olds.

Where would you start with this? Work on the heads first? Decide on the stroker kit and then do the heads? Cam choice first?

Thanks
Drew
I found the guys at pontiac tripower steered me right when i did my tripower 2 years ago. Their recommendations for jetting and idle tube orafices worked out great.
I didnt have to bush my throttle shafts but i did replace the throttle shaft on my center carb As it was worn. I did put bushings in the air horns to tighten up the accelerator pump shaft slop.

my advice would be to take them apart carefully and see what is worn… not surprisingly my center carb had more mechanical wear on shafts and linakge than end carbs. If you have a set that no one has dicked with over the last 50 years you are leg up. Someone less than knowledgeable had previously been through mine and put wrong floats and accelerator pump parts in.
 

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Discussion Starter · #23 ·
If you have a set that no one has dicked with over the last 50 years you are leg up. Someone less than knowledgeable had previously been through mine and put wrong floats and accelerator pump parts in.
From the looks of the screwheads, They definitely aren't untouched.

Motor vehicle Gas Auto part Metal Nut


I did pick up the copy of Jim Hands book and there is some good info in there. Any headwork I do will be on the very mild side. I am mot looking for max possible airflow, just want to clean up the obvious stuff. In the book, Jim Hand ported a set of 6x-8's, but he did a full porting and polishing job. Way more than I will need for what I plan with the car.
 

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From the looks of the screwheads, They definitely aren't untouched.

View attachment 161276

I did pick up the copy of Jim Hands book and there is some good info in there. Any headwork I do will be on the very mild side. I am mot looking for max possible airflow, just want to clean up the obvious stuff. In the book, Jim Hand ported a set of 6x-8's, but he did a full porting and polishing job. Way more than I will need for what I plan with the car.
Hopefully no one mixed and matched parts from several 2 jets inside.
it was a fun project for me, first gto i bought back in 89 ish the seller had a 64 with tripower never forgot that sound. Just wish i had bought more parts. Used to see complete setups for $350-400 at swap meets.…
 

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Hopefully no one mixed and matched parts from several 2 jets inside.
it was a fun project for me, first gto i bought back in 89 ish the seller had a 64 with tripower never forgot that sound. Just wish i had bought more parts. Used to see complete setups for $350-400 at swap meets.…
yeah, i hear that. prices have went up a dollar or two since the 80s.
 

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Discussion Starter · #29 ·
I think that I will start with the heads first, then work my way from there. I emailed Butler yesterday in regards to what parts I would need. They suggested that I start with the machine shop. I will probably have it machined for 1.77 valves since I do not plan on extensive porting. I think I will also need valve guides installed and he did mention valve seats, but I have read that 6X heads are induction hardened and will not need new valve seats when going from 1.66 to 1.77.

I also assume that the heads will need to be resurfaced, but I do not think I want to take more than a few thousands off because I do not want to change the size of the combustion chamber too much.

I am not sure if I want to clean up the heads (grind the casting flash, etc,.) before taking to the machine shop or wait until after it is machined.

Any thoughts from you guys that have done this before is welcome.

Thanks
Drew
 

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I think that I will start with the heads first, then work my way from there. I emailed Butler yesterday in regards to what parts I would need. They suggested that I start with the machine shop. I will probably have it machined for 1.77 valves since I do not plan on extensive porting. I think I will also need valve guides installed and he did mention valve seats, but I have read that 6X heads are induction hardened and will not need new valve seats when going from 1.66 to 1.77.

I also assume that the heads will need to be resurfaced, but I do not think I want to take more than a few thousands off because I do not want to change the size of the combustion chamber too much.

I am not sure if I want to clean up the heads (grind the casting flash, etc,.) before taking to the machine shop or wait until after it is machined.

Any thoughts from you guys that have done this before is welcome.

Thanks
Drew
I like to do the match porting and flashing removal before the parts go to the machine shop. The benefit is that all that grinding and deburring throws grit and metal shavings everywhere and the machine shop should do a thorough cleaning prior to checking for cracks and such. The downside could be that the part turns out to be junk and you have wasted some time. The flipside is you may end up with grit where you don't want it if the parts are deburred afterwards. The only way I would do it afterwards is if the parts were still bare and had no assembly to them. This way you could flush them thoroughly yourself. Many will advise getting the parts back from the machine shop bare so that they can be bottle-brushed out...It's amazing what a shop can leave in an engine for your oil screen and filter to catch! This typically requires the owner to be able to assemble it themselves or return it to the shop for assembly.

As far as which part/s to start with...you have to consider them all (especially the head assemblies, block, crank, & pistons...then intake, exhaust mani's or headers, carb, and cam) at the same time which can get a bit overwhelming. This is how am am going to have to start my build process (maybe late this year)...

What I have to start with....

1.) a used 400 block that has been bored 30 over already and will need a slight bore to freshen it up.
2.) a used set of 670 heads that will require deeply dished pistons to run well on today's gas and hardened seats.
3.) the new pistons will have to be custom to accommodate the dish and the non standard bore for just beyond 30 over (I do not want to take them to the next standard bore size so that the block might have additional life in the long run).
4.) a 400 crank that mic'd well and probably would just need a polishing, BUT my goal is to approach 500 HP. SO, I am going with a stroker kit to increase the HP and gain back what I lost in reducing the compression ratio.
5.) a stock cast iron intake that has been port matched and has a poor-man's blend. I read that these intakes are about as good as they come for this power range.
6.) a set of HO 2.5" exhaust manifolds.
7.) a well used remanufactured QuadraJet that was purchased in the late 80's that needs full attention.
8.) and, cam consideration all depends on how the above parts evolve.

I plan to take my heads and block to the machine shop (I have already port matched and deburred them along with opening up the oil return holes). They will tell me, for sure, that the parts are good to used and what bore to shoot for. If something turns out to be cracked...it could change my direction. This is why I need all my parts checked out all at once. For example: If my heads or block are junk...I'm back to the drawing board and subject to what core pieces I can source. A 455 block may not want my heads (or vise-versa) and it would have been a shame to have spent money on restoring some of the parts that may not fit the build in the long run.

Then, I will have to get advise from here, a select friend or two, and places like Butlers to determine what size to stroke too. I'd love to go all the way, pushing the 500 cubic inch kits, but don't know enough about the ramifications at this point. My intake and/or exhaust mani's may not be up to that or block modifications may be required...I don't know yet.

At this point, I should be able to chose and order a stroker kit with the custom pistons. Of which, I would supply to the machine shop so that they can bore the block to the new pistons. I hope to do all the assembly myself.

Meanwhile, the above decisions and previous discussions with the experts mentioned above should lend themselves to a cam selection followed by the carb build or purchase.

There's a lot to it, but the point is...much of it has to be tackled at the same time to avoid over spending and/or ending up with parts you don't need. The trick is patience and the funds to do these chunks at the same time.

As far as surfacing the heads (or Block), the machine shop should be able to estimate how much needs to be removed. Then give the exact final amounts removed when complete. These numbers will dictate the custom pistons (if needed) or which standard pistons can be used to meet your goals. Many years ago people would shave the heads and/or block to up the compression, but those days are over for pump gas. Now, you want to remove as little as possible (in most cases and especially on slightly over stock builds). I would strongly consider going with larger valves even if the goals are not lofty enough to need them. Larger than needed valves do not deter from a build, within reason. Smaller than needed valves can be a problem you cannot overcome easily after the fact.
 

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I think that I will start with the heads first, then work my way from there. I emailed Butler yesterday in regards to what parts I would need. They suggested that I start with the machine shop. I will probably have it machined for 1.77 valves since I do not plan on extensive porting. I think I will also need valve guides installed and he did mention valve seats, but I have read that 6X heads are induction hardened and will not need new valve seats when going from 1.66 to 1.77.

I also assume that the heads will need to be resurfaced, but I do not think I want to take more than a few thousands off because I do not want to change the size of the combustion chamber too much.

I am not sure if I want to clean up the heads (grind the casting flash, etc,.) before taking to the machine shop or wait until after it is machined.

Any thoughts from you guys that have done this before is welcome.

Thanks
Drew
i had my 6x-8 heads reworked with 1.77 exhaust valves the machinist did not list putting hardened seats so you can get away with just cutting for bigger valve. i put over 60,000 miles on them. they are still doing great.replaced the original valves with stainless though. i don't know if that has anything to do with it.
 
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