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1970 GTO info

I have a 1970 Pontiac GTO that i am restoring. It has the original matching numbers YS Code 400 HO engine. When I got it a few months back, it sounded pretty rough. We removed a valve cover and found a bent push rod. At that point we decided a complete rebuild was in order. We removed the motor and transmission from the car. I’m want to know if the transmission is original to the car but I don’t know how to check the numbers for that. However, I could have found a clue. When we cleaned the motor and transmission I found the motor had been painted twice - the factory color with another blue over the top of it; the transmission had never been painted! Did GM ever produce cars and send them out with unpainted transmissions or has it just been replaced at some point?

Can you find the tranny number?? If so then a Pontiac dealer might be able to help…or try to find a forum for Pontiac’s or GTO’s.

The tranny may be valid for that vehicle…but are they matching numbers?? And do you care???

Great car BTW…Good luck with the restore…

Iron Engine Blocks Are Painted, But An Aluminum Transmission ? . . .

This stuff varies all over the place even among the basic Chevy brand (which I am most familiar with). Here’s a link to a site that is Chevy Camaro related but often can have similarities to the other divisions within GM. You may find this useful-

If you google ‘GTO’ you’ll find vendors and discussion groups with this kind of specialized information.

I have never seen an aluminum transmission that was painted. I assume that you have an automatic. Some older model manual transmissions with cast iron cases were painted.

thanks for the tips guys. I just painted the motor a few minutes ago… Just didn’t know if I should do the tranny as well. It cleaned up nicely so I may leave it as is. Thanks again for all that commented

It’s probably a T-400 but it could also be a T-350…You can tell by how many bolts hold the pan on…They were NEVER painted from the factory…

The fastest and most nimble Goat built was the 1964 model, the first year…They got heavier and slower every year after that…By 1970, the party was over for GM muscle cars…Chrysler and Ford held out for one more year…The 1971 models and newer were just echos of the past, all show, no go…

GTO = Gas . . . Tires . . . Oil

I grew up near Woodward Ave (in the burbs), one of the street drag racing headquarters of the era. In 63 or 64, my best friend’s sister had a H.S. boyfriend who bought one of the first 64 GTOs, a sleeper, beige, hub caps, and looked like your father’s Tempest, except the little logos. It was a goer.

I’ve never seen a painted aluminum transmission but that doesn’t mean yours is not original with the car. Someone could have done that at anytime in the past 40 years.
There should be some serial numbers on it, either stamped or on a small ID tag. You should be able to trace it back from those. Maybe you could get a little advice from the Pontiac Owners Club, which I beieve is the group that maintains a complete Pontiac history with help from GM.

My sister owned a 64 GTO way back when and she sold it back in the late 70s for 300 dollars, straight, running well, and factory A/C. Oh, how the values have changed.

By 1970, the party was over for GM muscle cars

Not quite from my recollection.
The 1970 LS-6 Chevelle was no slouch at >450hp.
1971 still had a 425hp version.
By 1972, the rubenesque lady was at full volume…

The first half of 1970 were OK. In mid year, they changed over to 70 1/2 models where they got heavier bumpers and lower compression in order to comply with hastily written legislation.

My all time favorite Muscle was my 67 Malibu SS with the 327…LOVED that car…Wish I still had it. Yea the 396 had a lot more power…but I LOVED that engine…The two-speed power-glide was extremely durable…My only gripe was I wish I had the manual…

A 300hp-327 , not to mention the rare 350hp version, on a drag strip or street race, could usually best the 396’s regardless of advertized horsepower…They just got moving quicker…That first 100 feet makes all the difference…

The 1964 GTO was a prime example…The “standard” engine in that car was a 325hp 389 single Quadrajet 4-barrel…But for a few dollars more, you could get a 348hp (rated) engine with the “Tripower” (3 duces) carb set-up…

At the drag strip, the single 4 barrel Goats were always faster…

Here is everything you could possibly want to know about a 1970 or any other year Goat…

Guy at the gas station had one of those Goats with the ‘Tripower’ - he was always working on the carbs, trying to get them working right…not the best mechanic there…

That first 100 feet makes all the difference…

Story from a guy at work had one of his buddies in an 80s IROC Camaro racing a guy street light post to street light post(about 50 feet, give or take) on foot.
Guy in the Camaro was bragging how fast his car was, the other guy saying it was slow as heck. Few beers later, the race was on. Sad part is, the guy on foot was pretty close both times, and may have even won one of the races.

keith, that’s not correct based on what I recall, the cars I own/have owned and the information reported on numerous web sites. I own, and have owned, quite a few big block chevy’s from those years. Built and restored many of them. Raced for years and had blueprinted and modified engines dynoed. At any rate, the compression on LS5 and LS6 did not change until 1972. Here’s just one reference if you don’t agree-

BTW, I still own one numbers matching 1971 LS6 Chevelle. Prior to modifying it for class drag racing, I had dyno runs done on the motor. The OEM used engine straight out of the car came in around 425hp but was somewhat worn. Naturally aspirated and built by me to meet certain performance specs on pump gas, it came in around 490hp.

I read your reference, but I am going to stand by what I said, but with one caveat. I am going by memory here only, but the sudden drop in compression required by the feds came mid year. It might have been midyear 71 instead of 70. Actually it may have been required by Jan 1, 1971 but about half of the years production (production for the next model year starts right after the July 4 shutdown week) would have been done by then.

Your reference confirms that the drop in compression was mandated in 71, but half the years production would have been done in 70 so that would explain why you have the vehicle you have, you lucky dog you.

OK I see what you’re saying, I was speaking strictly in model years, not calendar years. About mid year 1971 the effects would have made it into production and that would be the 1972 model year (the beginning of the dark ages).

Good, I thought my memory was going and I was on the verge of being able to hide my own Easter eggs! :wink: