[1965gp]

I am going to look at a 350 tomorrow that was pulled from a running and driving Firebird. The motor is a stock 73 350 with 4c heads.

The motor in my 66 GTO runs but not well. The shop I use said there was something wrong with the one of the heads and I was going to have to have the heads reconditioned. I use the shop all the time and trust them.

The 66 GTO has a 400 in it with (I think) 62 casting heads. I have an extra set of heads I can put on it and go on with the motor in it or put the 350 in it.

The 350 was on a chassis dyno when it was in the car and dyno’d 185 to the rear wheels. Not impressive but not far from what I would expect from a stock 66 389.

So my thought was that this 350 ran well enough that I could put it in the car. I have a Tri-Power for the car I would like to put on whichever motor I use. So does it make sense to put the reliable 350 in the car with the Tri-Power? Do I change the cam or is that too much for the small valve heads?

It would probably be easier to just swap the heads, but then again I do not know the condition of the bottom end/cam.

Thoughts?

[steve25]

Well there's a couple of things you could do here!

If you i idea of what condition the rest of the 400 was in you could put the heads from the 350 on it and either drop the compression of the 400 down to a more livable amount if it was a high comp motor, or bring it up to a good level if it was low comp motor.

You could run the 350 as is while you save up funds to rebuild the 400, but one thing I would not do would be to put the tripower on the 350 as it's looking for a higher level of vacuum like from a high comp 389 or 421 .
It would likley take a good amount of center Carb tuning to get the 350 to idle clean.

[1965gp]

Good advice! I think I am still going to get the motor as it’s a nice back up for any of the other cars and the price is right.

[Lee]

Come on over Jeremy, I'm already up!

[redhawk44]

When I purchased my car the guy had small heads on the 400. I think they are a 17 on the right side and a 47 on the other. The car ran very well, as far as reliability goes. Sucked as far as performance goes. What Steve said about swapping the heads until you rebuild the 62 heads makes sense.

[Cliff R]

A cam swap into a low compression 350 never helps much. For every 10 degrees you increase duration you'll need another full point of compression to keep it happy.

I've been watching countless folks cripple low compression 350 SBC engines for decades with the famous 204/214/112 "RV" camshaft. Without going to flat top pistons and/or smaller chamber heads the RV cam just kills off some low end power and pushes power up in the RPM range. The stock replacement CS-274 camshaft is a far better choice for those engines....IMHO.

Anyhow, I would run the Tri-Power on it, for looks more than anything else. You can tune the center carb so it runs fine and sips fuel for "normal" driving. Kind of cool and you never have to tell anyone a 350 sits under it........Cliff

[Dragncar]

I put 48 heads on a 69 350 with the "214 high lift" can it ran pretty good. Sounded sweet. Ran mid 15s in a 69 A body with stock everything else.

[pastry_chef]

Depends on the goal and other components.

Attached are dyno tests for a 8.8 compression 350 SBC, small valve heads 1.94 intake valve - 200 CFM port. Performer intake.

If a guy was going to run a 3000 stall converter the 265 DE Comp is stronger everywhere! Up an amazing 100 horsepower at 5500 RPM. still has 16 inches of vacuum.

[Steve C.]

Generic build....

"Rebuilding A '69 350 H.O. That Believes It's A 400"

Pontiac 350
330 hp at 5200 rpm
Cam
Brand: Melling SPC-7 (No. 068 replacement)

https://www.hotrod.com/articles/hppp...-engine-build/



.

[pastry_chef]

Originally Posted by Steve C.

Brand: Melling SPC-7 (No. 068 replacement)

Would be awesome to see what a Voodoo 702 would do in that engine. I'd guess at least 15 HP more peak and more midrange.

Originally Posted by glhs#116

Well, my experience so far moving from an 068 clone (Melling) to the Lunati Voodoo 702 is that you can get the low speed manners of the factory cam with a hell of a lot more on top with the newer cam profile. I would say at idle and low RPM the engine now is very hard to tell from when it had the 068 in it. I'm pretty confident it will pass emissions like the 068 did. Idles just as slow and strongly. Pulls from idle just as well. But it's got a whole new set of lungs up top. I'm not done with break-in so I haven't really wound it out but it is pulling hard at 5,000rpm where my 068 was already losing interest. And it pulls at all rpms like the 068 never did.

[1965gp]

Thanks for the replies guys. It was great meeting Lee today and picking up the motor.

My plan for the 350 would be to not rebuild it. Put the Tri-Power on it and set it up for the smaller displacement. With long tube headers the car would probably make close to 200 hp at the wheels.

I am still considering pulling the heads on the 400 and swapping them to see what happens. I can’t seem to make up my mind.....

However I did get the motor cleaned up today.... hate looking at a dirty engine even if it’s on the shop floor!

[64speed]

When I got my car the 326 had tri power on it. I can tell you from experience don’t put that on the 350. I’d run the 350 and save up to build the 400. Just my opinion

[steve25]

How does the 400 test out cranking comp wise?
You said one head had a issue, what is that issue?
Is it's oil pressure ok?
Is it's timing chain shot?
A loose chain Cam murder your cranking compression numbers!

If your compression tests ok and you start off by pulling that bad head do that you can look at the Bores , if they look good with only a minor carbon lip at the top then I would plop the 350 heads on it .
The only down side to running the 350 heads is if it still has its pressed in rocker studs because if that is the case then running a Cam of over .450" lift with its needed spring pressure becomes iffy that you may yank one out , or snap one off where it's threads start off.
Ask me how I know this ? Lol!

[Lee]

Dang!! She cleaned up well!

I enjoyed meeting & talking you with you too, Jeremy, and nice to know the old motor has such a nice new home :-)

[beertracker]

I don't know your budget but I would consider stroking the 350 to 383. bt

[1965gp]

Well, there is nothing wrong with the 350 and I have several cars that it is a great back up for. Lee said the motor ran well so I don’t see any reason to rebuild it at this time. If I was going to build anything it would be a 400.

As suggested I think I am going to pull the heads on the 400 in the car and see what it looks like. The car has already been through a thorough restoration before I got it so it may have been rebuilt.

[Squidward]

Woo hoo! Another 350p in the sandbox!

Summit 2800 is a great mild performance cam swap for a 350, and requires no other mods to valvetrain.

702 Voodoo cam in a 350 is a good runner, and has put me at 14.06 with more left on the table. That cam requires head upgrades, tho.

I always loved the 69 350 HO build article in Hot Rod.

Keep us posted on the tri-power conversion! Sounds cool, not because the 350 is going to be a forever motor, but because, like, nobody does that!

[ho428]

Originally Posted by Squidward

Woo hoo! Another 350p in the sandbox!

Summit 2800 is a great mild performance cam swap for a 350, and requires no other mods to valvetrain.

702 Voodoo cam in a 350 is a good runner, and has put me at 14.06 with more left on the table. That cam requires head upgrades, tho.

I always loved the 69 350 HO build article in Hot Rod.

Keep us posted on the tri-power conversion! Sounds cool, not because the 350 is going to be a forever motor, but because, like, nobody does that!

Whadda ya mean, nobody.
365 cu in, shaved and ported 17 heads w/ 2.07 intakes and screw in studs, T2 intake, 750 carb, solid flat tappet, backed by an M20, replacing a base OHC until I get a Sprint built.

[Squidward]

Originally Posted by ho428

Whadda ya mean, nobody.
365 cu in, shaved and ported 17 heads w/ 2.07 intakes and screw in studs, T2 intake, 750 carb, solid flat tappet, backed by an M20, replacing a base OHC until I get a Sprint built.

Doh!

What I meant was trips on a 350p. There are other players in the 350p game, but I never see the tri-power on the 350. Most tri-power guys don't waste their time on a 350 build.

I am with you, brother! Fly that 350p freak flag proudly!

[torqhead]

Originally Posted by 1965gp

Well, there is nothing wrong with the 350 and I have several cars that it is a great back up for. Lee said the motor ran well so I don’t see any reason to rebuild it at this time. If I was going to build anything it would be a 400.

As suggested I think I am going to pull the heads on the 400 in the car and see what it looks like. The car has already been through a thorough restoration before I got it so it may have been rebuilt.

If possible I would maintain the 400 with the 62 heads, there are several cam options that will work just fine with those heads and produce good streetable power. Put a good cam in it, 224/230 with lift around .500 and it really makes the motor breath and runs well on regular gas no issues. Obviously your rockers will need to be adjustable. I just built this combo for a friend of mine and his 66 now flat out moves, it's biggest negative is it's topped off with a Holley... lol