[1965gp]

So what would you do…..

Background info- 72 TA clone with a 400 out of a 67 GTO bought running when the owner converted to an LS platform.i stalled it and it ran great. Leaked a little oil but I figured it was from the vid awful chrome oil pan. Installed and drove it for a few years until the oil leak started to get worse.

Took it to a friends shop to have the rear main seal replaced, this is what they found:

[1965gp]

Rear main cap was cracked and had three divots in it like it was hit by a big punch? Turns out these divots line up with the flywheel bolt holes. Not sure why or how this would have been done, I’ve never had the flywheel off the car.

So I am faced with a few choices. Here are pics of the car

[1965gp]

So we replaced the main cap to see what happened and as we feared it’s leaking from the back of the block too. Motor has to come out and I have to assume they ran bolts into the back of the block just like the main cap.

Option 1: I have a good running 69 350 HO with the 48 heads. I can detail it and throw it in the car. Problem is the car sounded awesome and rowdy. This won’t.

Option 2: Install the 350 HO and add a cam/lifter set up. This would work well with the looser converter, fuel system and give me the sound I want. But it’s a 350.

Option 3: Complete the resto mod me top look and put an LS in the car. It has the aftermarket suspension, gauges, Vintage Air, wheels… it would make it a more desirable car to everyone except me. This is the most costly option.

Option 4: Hold out for a 455 and build it. This would be great but who knows how long it will take to find/build what I want and with Vintage Air this is a great car for summer so I would like to be able to enjoy it when it’s 100 deg and humid in Houston.


So what are your suggestions? Right now I think Option 2 gives me most of what I want with the least amount of downtime and still affordable.

[johnta1]

WOW!
They must have used a heck of an impact wrench on that.

Was the other car a stick shift and this is an automatic?

The bolts are a lot longer for the flywheel compared to flexplate.
But usually one can tell when they finger tightened and it stops with about 1/4" left before snugging up to flexplate.

Me, I'd go with a 455 as replacement.

[67Lemons]

I’d throw in the 350 with a quick detail so that I could be driving ASAP. Then I’d take my time to find & build whatever 400/stroker or 455 I could find within my budget, install the following winter.

[jhein]

Originally Posted by 67Lemons

I’d throw in the 350 with a quick detail so that I could be driving ASAP. Then I’d take my time to find & build whatever 400/stroker or 455 I could find within my budget, install the following winter.

That's my vote too.

[1965gp]

Thanks- what about a cam? Should I put one in? Does anyone know what a stock 350 HO wpukd have had or could anyone suggest a nice soundingcam for this application?

[JLMounce]

A stock 350 HO would have had a number of cam possibilities depending on how the car was spec'd. 067, 068 and 744 as far as I'm aware.

I know you want this thing to sound radical, but I think the prudent thing to do right now is to simply put your good running 350 HO in the car. You'll still be able to enjoy the car while you save for your next engine.

And, if anyone ever asks, you can tell them exactly what you just told us. You lost the previous engine and you're up and running while you build a new one.

I like Poncho's in between the frame rails. I'd find that 455 and build it. I'd only do the LS if I was trying to maximize selling price with the intent to sell.

[mgarblik]

Nice looking car first of all. I would either build a 400, 400 stroker or a 455 for the car. A 350, no matter what you do with it won't have "Trans AM" performance without spending 2-3 times what a 400-455 will cost. That car with AC is close to 4000 lbs. A 350 will struggle to produce a performance level most would be happy with. Think of it like putting a 305 in a second gen. Z28, but probably a little worse. Although a 350 HO is a cool little engine, you would be giving up about 100 ft. lbs. of torque to it's big brother.

[Squidward]

350!! Your performance ceiling will be lower, but unless you drive like a complete psychopath, not much more performance is useable. I leave a significant amount of my 350's performance on the table when I drive.

I run a 350 with RA #12 heads and Lunati 702 cam. It cost me no more to build than a 400 or 455. It gets way tougher to find forged pistons off the shelf, but that is the only limitation. Cam choice has to be thoughtful, combined with rear gears and converter selection. If you already have a drop in ready 350, go for it while you find your big inch dream.

I have a 400 destined to go in my Firebird, but sometimes I wonder "what's the point?" other than to say I have a Firebird with a 400. Am I marketing it to myself? The 350 gives me all the driving crazy I need. Your 72 probably weighs a good 500 lbs or more than mine, so that might make a difference that you won't be able to live with.

That's a beautiful car, BTW. 2nd gens, especially the early ones, hold the most dear automotive place in my heart.

[scott70]

Originally Posted by Squidward

350!! Your performance ceiling will be lower, but unless you drive like a complete psychopath, not much more performance is useable. I leave a significant amount of my 350's performance on the table when I drive.

I run a 350 with RA #12 heads and Lunati 702 cam. It cost me no more to build than a 400 or 455. It gets way tougher to find forged pistons off the shelf, but that is the only limitation. Cam choice has to be thoughtful, combined with rear gears and converter selection. If you already have a drop in ready 350, go for it while you find your big inch dream.

I have a 400 destined to go in my Firebird, but sometimes I wonder "what's the point?" other than to say I have a Firebird with a 400. Am I marketing it to myself? The 350 gives me all the driving crazy I need. Your 72 probably weighs a good 500 lbs or more than mine, so that might make a difference that you won't be able to live with.

That's a beautiful car, BTW. 2nd gens, especially the early ones, hold the most dear automotive place in my heart.

I’m the opposite. I have a 480 hp 455 in my 70 gto and I frequently use all of it when I drive. If it was a daily driver I might cool it some but I like feeling how it feels pinning you in the seat as you row the gears. It never gets old. As a matter of fact I’d like more power. I had a 625 hp 455 in a 72 lemans and was still always looking for a little more.
Yes throw in that 350 and build a 455 or 400 stroker in the meantime. That HO should still give you a decent pull and not feel like a complete pooch. If you want some rump for sound effects you can throw in a cam ,,, maybe a 224/234 cam.

[1965gp]

I appreciate all of the insight- the goal is to enjoy the car and honestly my wife likes driving this one so it’s important to keep it one piece.

I don’t really beat on my cars and to be honest I don’t even get to drive them that often. I like to hit a cruise on the weekend otherwise I just drink beer and look at them.

I have several projects apart right now so the smart move is probably to drop in the 350 as is and enjoy it.

There is another option- I have a later model 350 I bought from a member here that said it drove great in his 2nd Gen and had gotten it to have decent power. I think it has 5c heads on it. I could pull the 670 heads off my motor and put them on the 350 if that would help.

[1965gp]

The only reason the sound is important is that the car sounded so bada$$ before I think it will feel like something is missing

[SD455DJ]

I'd throw in the 350HO engine temporarily and build the 455 in the meantime. The 350HO is a fine 'little' motor. I have a 350HO equipped '69 Custom S 4-dr sedan and it weighs 4000+ lbs with my butt in it. Your TA is probably close to the same weight. It has the TH400 auto and the standard 3.55 rear end, all stock and it manages easy low 15's at 92 mph letting it shift itself (4800 rpm). Depending on your clone TA's rear gear, it would be 'peppy'. Auto 350HO's came with the 067 cam, sticks with the 068. The 744 cam was proposed but never saw the light of day...I can't believe PMD ever considered that cam since the 067/068 are plenty for the 350...especially with the big valve 48 heads and the valve shrouding they create. You will need the motor mount adapters as the '69 and earlier blocks aren't cast to with the bosses for the 2nd gen Birds. Nice Bird btw...

Dennis

[Held for Ransom]

Originally Posted by SD455DJ

I'd throw in the 350HO engine temporarily and build the 455 in the meantime. The 350HO is a fine 'little' motor. I have a 350HO equipped '69 Custom S 4-dr sedan and it weighs 4000+ lbs with my butt in it. Your TA is probably close to the same weight. It has the TH400 auto and the standard 3.55 rear end, all stock and it manages easy low 15's at 92 mph letting it shift itself (4800 rpm). Depending on your clone TA's rear gear, it would be 'peppy'. Auto 350HO's came with the 067 cam, sticks with the 068. The 744 cam was proposed but never saw the light of day...I can't believe PMD ever considered that cam since the 067/068 are plenty for the 350...especially with the big valve 48 heads and the valve shrouding they create. You will need the motor mount adapters as the '69 and earlier blocks aren't cast to with the bosses for the 2nd gen Birds. Nice Bird btw...

Dennis

I assumed since he had an engine out of a '67 GTO, he would already have the adapters.

[67Lemons]

With all the cam troubles out there I wouldn’t jeopardize cruising season by swapping a new cam, I’d just run it the way it is & focus on my engine build for the following season. It’s a nice car that needs to be driven o go drive it.

[thepontiacman]

Keep Pontiac V8!!!


Many Pontiac Engines available here at my place in AL.
PM if you want number.

Sent from my moto g power 5G - 2023 using Tapatalk

[Gator67]

I hate doing things twice, and I love bigger engines in my cars, so I’d put my time and energy into sourcing a 455/400 stroker from a reputable builder. The car might be off the road a bit longer than ideal, but it would provide an opportunity to exercise other cars in the stable. Though, if you were perfectly happy with the 400 other than the leak, and given how you use the car, I suspect you’d also be happy with the 350 with a cam that gives you the sound you like.

[72projectbird]

Originally Posted by 1965gp

Rear main cap was cracked and had three divots in it like it was hit by a big punch? Turns out these divots line up with the flywheel bolt holes. Not sure why or how this would have been done, I’ve never had the flywheel off the car.

So I am faced with a few choices. Here are pics of the car

Awesome car, and sweet garage! I have a GN also. It's funny how a lot of us here are into similar stuff.

As for what I'd do? I'd entertain almost any drivetrain. I have both traditional Pontiac powered cars, and LS swapped Ponchos. They're both fun.

I'll say this, if you go with a stock 350 Pontiac to get it running, that's more than fine, but please don't try and convince yourself that it's plenty for the street, because it's not.

[SRR]

A big valve 350 is no slouch! Any car that sits non-running will develop issues. Drop it in, your wife will hardly know the difference.