# What Powers your Poncho?!



## Orion88 (Apr 24, 2012)

Ok, so I did a quick search on this forum and couldn't find a thread where people could post engine build specs, dyno sheets, quarter mile times, etc all in one place, so I thought I'd start one.

We all know that there are limitless ways to turn these heavy old Goats into neck-snapping beasts... stroker kits, aluminum heads, super/tubochargers, Nitrous, LS swaps (not my favorite), the list goes on and on. And with so many great engines offered by Pontiac in the 60's, the combinations are endless.

SO... what powers your Poncho?? Whether it's your original '64 389 or a beastly aftermarket 421 SD crate motor, I want to see different types of builds compared to each other side-by-side. How does a dyno sheet from a 461 stroker compare to a 389 tri-power? What was your quarter mile time with your bone-stock 455? Did that 572 Chevy crate engine you swapped in make you forget all about your original 400 RAIII? How do your horsepower and torque ratings compare to what your engine was rated at from the factory? How much did your build cost and are you happy with the results? Who did the build, you or a shop? Basically, I want this thread to be a place for those of us who bleed Pontiac Metallic Blue to share our stories of how we keep those SS396 Chevelles and 428 Cobra Jets in our rear view mirrors where they belong!! 

I know some people are very secretive and touchy about their engine modifications, but I know there are plenty of members on this forum who love talking about this kind of thing, so hopefully this will be a fun topic, and I expect to see a lot of very interesting builds, GoPro drag strip videos, and dyno sheets!!!


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## BearGFR (Aug 25, 2008)

Ok, I'll play 

The 400 in my 4000 lb '69 is the one it was born with - numbers matching.
It's now wearing a 4.25" stroke Eagle crank, 6.800" Eagle forged rods, KB Icon forged pistons. Static compression ratio right now is 10.0:1. I'm running Edelbrock round port (72cc) heads, ported and modified by Dave Wilcox at CVMS. Intake valves are 2.190, exhausts are 1.77. The cam is a custom Comp Cams grind, solid roller, 236/242 @ .050, 110 LSA, installed at 106, gross lift of .622/.629 at the valves. The rest of the valve train consists of Howards springs, titanium retainers, Scorpion 1.65 roller rockers, Jomar stud girdles, and Comp Cams 9-way adjustable billet timing set/double roller chain. For ignition I'm running a DUI HEI with 20 degrees of travel, installed to give me 37 degrees total at full advance. Oil pump is a Melling M54D with a Nitemare performance laser-grooved backing plate and Nitemare positive retention drive shaft, Milodon pan and windage tray. Main bearings are Federal Mogul, rod bearings are King, rings are Hastings. It has an SFI-rated balancer and flex-plate. Intake is an Edelbrock Torker-I single plane under a gen-u-wine 800cfm 455SD QJet. Headers are Dougs, Jet-Hot coated. Transmission is a beefed up TH400 with all the good stuff behind a 10" 3200 rpm converter. Rear is a Moser 9" with 3.50 gears and Wavetrac diff. Brakes are Wilwood Dynalite 4-piston all around. 

The car has run a best so far of 11.89 @ 113, just leaving it in drive and letting it shift at about 4900 rpm.

When I first built and dynoe'd the motor, I built it with real #722 69 Ram Air IV heads. Unfortunately, one of them developed a crack later so that's the reason it's now wearing E-heads. They actually make more power than the RA IV's did, but they're not quite as "cool".

Here's a link to the dyno sheet with the Ram Air IV's (and a carb mixture that wasn't quite dialed in. It probably picked up another 20-30 HP with the E-heads).

http://www.garrettfamily.us/gto/docs/bestdyno.pdf

(I hope it works - I've been having some problems with my new server that I've not quite figured out)

Bear


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## Orion88 (Apr 24, 2012)

Very nice, Bear! Of all the things you listed the one that caught my attention the most was your original 455 Super Duty Quadrajet. Those are not easy...or cheap... to come by!! Where did you find such a carburetor? Personally I would have sold the SD Qjet to someone who wanted it for their SD455 T/A build and used the profit to get a run-of-the-mill Qjet rebuilt by Cliff, and whatever was left over would have went under the hood as well. But it is very cool to say you've got such a rare carburetor on your engine. Thanks for the post! I was hoping you'd chime in here!!

I unfortunately do not have all of the specs on my motor. The car was bought by my dad as a surprise to me and I don't have a detailed list or a dyno sheet like Bear does. I do know that it's running an Edelbrock 1405 carb/Performer Intake combo up top, and it has a cam that is a step above the Ram Air III cam. The rest of the internals are all pretty standard. Around September of last year I swappd out the smog-era 6x heads with a set of #13's I picked up for a good deal. I would imagine I am in the 380-400hp range. I've never had it at the track but I did spank a Supercharged Mini Cooper with only about 3/4 throttle. Transmission is a B&M built TH400 and will handle most any engine I could throw under the hood. Rear is a Posi 3.08. I will be rolling with this same setup for the first couple years after my restoration is complete, but once I have a real job and real money, I plan on giving Bear a run for his money!!!!


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## BearGFR (Aug 25, 2008)

I bought the carb years ago from H-O Racing, back when you could still get them from GM. It was a brand new, service replacement carb, still in the box. Number 17054910 if my memory is correct. This is the first engine it has ever fed.

Bear


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## Orion88 (Apr 24, 2012)

I was thinking this would be a pretty popular thread. I guess people don't feel like comparing engine builds.


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## Matthew (Feb 11, 2011)

Orion, well, I have a straight up 400 HO. I don't have a dyno sheet or quarter mile time. I did bark the tires off a stop light a couple weeks ago when this elderly couple in the lane beside me revved their engine and looked my way. I clearly have more HP than the Buick Regal they were driving. Oh, and I did save money last year with USAA insurance - I just don't think the 15% thing with Geico will work for me. All good. Matt


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## Orion88 (Apr 24, 2012)

Very nice. I've only drag raced mine once at a stop light. Had a kid in a Supercharged Mini Cooper who wanted to have a go. I gave him what he asked for... with a modest 1/2-3/4 throttle. Once I put mine back together I hope to have some better stories than that.


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## JVM225 (Jun 18, 2007)

Mine is still powered by it's born with engine, heads, intake, carb, distributor, turbo 400, etc. No problem coming off a light, and even gets a nice chirp shifting in to 2nd if I keep the go pedal planted. 
Never dyno'ed, but torque feels great when nailed, and it's had a couple of favorable stop light contests over the 16 years I've owned it.
I don't beat on it regularly, but every once in a while I like to drive it like I stole it. I think the car likes it too.
It will never keep up with my C6 Corvette, and the thrill might be a little different, but it is just as much fun to drive.


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## Norms68 (Jul 17, 2013)

Currently my 1968 GTO has a correct year YS 400 with #16 heads, TH400, iron intake, service replacement quadrajet, and d-port exhaust manifolds. It can burn the tires from the stop light and shifts hard with a 2nd gear chirp.

It wasn't enough for me so now I'm building a 461 stroker out of a 1971 block. Videos below if you want to take a look.


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## geeteeohguy (Feb 2, 2008)

Can't give much info since both of mine were built so long ago. I built the '65 389 that's in my '65 GTO in 1981, when I was 20. My first 'motor'. .030 over, forged Sealed Power flat top pistons, stock rods shot peened and polished, crank chamfered at the oil holes, Clevite bearings, Weber flywheel, McCleod clutch, all balanced/'blueprinted'. All clearances dead on factory spec. Hand filed chrome rings. Sig Erson Hi Flow 1 camshaft, single pattern. Stock 77 heads, 3 tube Hedman headers, tripower. This engine screams, but now needs race gas due to its high compression. Has 50k miles on it, 33 years down the road. No oil consumption, and, no oil leaks. This engine ran 13.55 when I had it in a '66 GTO with a 4 speed and 3.55 gears. Currently, in my '65, I have 3.36 gears and the original '65 tripower on it my car was born with. This engine ran a bit harder when it was in my '66 with the larger '66 tripower set up. My '67 has its original 400, bored .030, stock rods, 068 cam, original Qjet and exhaust manifolds. I built it in 1988. I installed lower compression heads 5 years back, and resealed the whole engine (rear main leak) about 3 years ago. It's a good runner in my 'cruiser' '67 GTO ragtop with a TH400 trans and a 2.56 rear gear. When I did these builds, no aftermarket heads, cranks, and rods were available. Been toying with the idea of some aluminum heads for the 389 so I can run pump gas and save some weight. I would love to do a build currently, with all the new 'good' stuff available, but I've got nothing to put it in.


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