[69hardtop]

Originally Posted by ponyakr

There's usually one or more of us old timers that will have a story about most any Pontiac engine mentioned.

I only ran across one of these engines, in my life. Back in the mid '70's, a friend had one in his '70 GTO. Don't remember now exactly how many miles it had on it. But it was less than 100K.

The engine developed a popping & coughing sound. He didn't wanna spend any money on having it fixed, & didn't really want another 455. So, he bought a good junkyard 400 for it. There were plenty of 'em back then, even in my area.

He knew I worked on & raced Pontiacs. And, I had a nice metal shop that was only about a year old. So, he hired me to swap in the 400. After I got his car running, he told me I could have the 455 if I wanted it. I did !

Pulled the intake & valley pan to see if I could find the problem. Yes. A lifter had come apart, therefore an exhaust valve was not opening at all. That explained the popping & coughing.

So, I replaced that cam/lifters with an 041 clone & Rhoads lifters. I think that first 041 was a Crane brand. Also went with a new TRW stock replacement timing set, & a Mr. Gasket advance key.

Put that engine into the '68 Bird TJ had raced toward the end of '76. It had run 13.20's with a 350. After I put some bigger slicks on it, it ran 12.40's at Green Valley Race City, in the D/FW area. Below is a pic of that car, at that race.

Towards the end of that '77 season, I put that 455 into my '69 GTO. Since that car, with me in it, was a lot heavier, it ran high 12's. But, that was good enuff for me to win the last race of the season, at our home track, & several in '78. .

Towards the end of the '78 season, I pulled the 455 out & put it into another '68 Bird, which a young friend raced. It ran mid 12's. Don't know how many passes that 455 had on it. But, it had to be several hundred, since we raced in 45 races in '78, and quite a few in '79.

So, my opinion of the '70 455HO is that the only problem with it was that the cam was much too small. If they'd used the 041, it would have been an awesome street engine. Obviously, forged rods & pistons would have been a plus. But, up to 5500 rpm. it was great.

Hey, it's just a small part of Pontiac history, involving the '70 455HO.

By the way, a guy named Todd Kuhn has been racing a '70 455HO GTO Stocker for several years. It's the only one I know of. He runs low 11's in F/SA.

https://www.nhra.com/results/2019/lu...ock-eliminator

Well, the engine was dropped off at the machine shop this week, I’m “in line” for teardown and analysis this week. I think once we know what has to be done, I’ll start a new post on the rebuild.

I’m ready for all the cam choice suggestions/criticism I’m sure I’ll get.

[ponyakr]

"...I’m ready for all the cam choice suggestions/criticism I’m sure I’ll get..."


LOL !

Yeah, that's a good thing, 'cause it's comin, probably whether you ask or not.

Hey, cam choice seems to be one of the most popular subjects on this site. And, for a 455, the recommendations usually range from an 068 to a high lift HR from SD Performance, with plenty of options in between. And an LSA discussion/argument usually ensues.

[77 TRASHCAN]

Originally Posted by 69hardtop

Well, the engine was dropped off at the machine shop this week, I’m “in line” for teardown and analysis this week. I think once we know what has to be done, I’ll start a new post on the rebuild.

I’m ready for all the cam choice suggestions/criticism I’m sure I’ll get.

What type of cam are you considering? Hydraulic flat tappet, hydraulic roller???

[69hardtop]

Originally Posted by 77 TRASHCAN

What type of cam are you considering? Hydraulic flat tappet, hydraulic roller???

Hydraulic flat tappet, maybe a Summit 2802. I’ll know better once I get initial diagnosis from machine shop on overbore. I’d like to use the 64 heads and keep compression ratio around 9.5 to 1 so a lot to be decided yet.

[PunchT37]

Originally Posted by 69hardtop

Well, the engine was dropped off at the machine shop this week, I’m “in line” for teardown and analysis this week. I think once we know what has to be done, I’ll start a new post on the rebuild.

I’m ready for all the cam choice suggestions/criticism I’m sure I’ll get.

Cam arguments around here are like mud wrestling. Stay out of em if you don`t want to get dirty.

[69hardtop]

Well, updating this post after a brief wait at machine shop; mostly pretty good news:
- block cleaned up at .030 over
- crank very good shape, needs polish only
- heads good to rebuild, all new valves/springs etc
- stock rods reusable, no issues
So.......before I go into my rebuild parts choice, I’d say ahead of time that my goal is mild mannered but torquey street car. Engine going into a 1964 GTO/4speed/3.55 rear axle/RARE exhaust manifolds/Cliff rebuilt 270 RAIV quadrajet
I’m picking Icon forged pistons with a 15cc dish, reusing my rods, and the Melling SPC-7 cam (068 clone). With my 87cc heads I think I’ll end up around 9.5:1 cr
I know there are many more cam choices for more power and torque (I’ve probably read at least 50 posts on 455 cam selection) but I think my part selection will give me what I want
On a side note, I have experience with my other car, an original 1969 400 with 62 heads, 041 cam, 1.65 rocker arm, headers etc that runs super hard but idles poorly, sucks gas and when I get home from driving it I reek of unburned fuel.....not doing that with this build.

I respect everyone’s opinion in this forum, please play nice if you care to comment. If I’ve made any glaring errors in my expectations please let me know as I’m ordering parts in a few days.
I know ahead of time I’m leaving some power on the table - so reread the goal I stated earlier in this post. Thx all

[455abody]

I think that is a really good combo you put together, I am having my 455 built this winter using very close to the same combo. It should work very well Congrats!

[455abody]

I am using the high lift 068 Nunzi cam in my build, same specs as the 068 but 480 lift with factory rockers. I bought from Paul Spotts

[John Milner]

That will make for a really nice running engine that is easy on everything but your back tires.

[torqhead]

[QUOTE=69hardtop;6079502]
On a side note, I have experience with my other car, an original 1969 400 with 62 heads, 041 cam, 1.65 rocker arm, headers etc that runs super hard but idles poorly, sucks gas and when I get home from driving it I reek of unburned fuel.....not doing that with this build.
/QUOTE]

Not being sarcastic or punchy here... Not sure what carb you're running, but before making your decisions on the new build investing a bunch of money on a mild build that you may not be happy with you should take some time fixing the current motor. There's no reason that your combo should be using a ton of fuel and making you wreak when you drive it.

[69hardtop]

[QUOTE=torqhead;6079535]

Originally Posted by 69hardtop

On a side note, I have experience with my other car, an original 1969 400 with 62 heads, 041 cam, 1.65 rocker arm, headers etc that runs super hard but idles poorly, sucks gas and when I get home from driving it I reek of unburned fuel.....not doing that with this build.
/QUOTE]

Not being sarcastic or punchy here... Not sure what carb you're running, but before making your decisions on the new build investing a bunch of money on a mild build that you may not be happy with you should take some time fixing the current motor. There's no reason that your combo should be using a ton of fuel and making you wreak when you drive it.

You make make an excellent point, but that older 400 I didn’t build and the whole combo was not put together correctly. It’s in a 69 GTO with a turbo 400 and 3:23 rear end (unknown stall converter) it’s a pig all around and just about untunable

The new 455 build will go in my recently completed 64 GTO

(I have the good fortune of having enough garage space for two Pontiacs. The 69 I’ve had for over twenty years, the 64 seven years)

[pastry_chef]

Originally Posted by 69hardtop

I’ve probably read at least 50 posts on 455 cam selection) but I think my part selection will give me what I want

Thumbs up and respect for doing that "homework" and taking ownership of your decision.

[scott70]

I dont know if youve cc'd the 64's but most are not 87cc. Mine came in at 93. A 455 with 9.5-1 comp,,RA 4 cam with rhoads lifters,stock intake and 1.65 rocker will rip and idle fairly smooth!! Its a proven combo

[69hardtop]

Originally Posted by scott70

I dont know if youve cc'd the 64's but most are not 87cc. Mine came in at 93. A 455 with 9.5-1 comp,,RA 4 cam with rhoads lifters,stock intake and 1.65 rocker will rip and idle fairly smooth!! Its a proven combo

Thanks for the info; my heads came in at 89 and 90 cc, pretty close to as built specification. They were virgin heads

[Bill Eveland]

Nice, i just picked up a 70 bonneville with a complete 60 k mile xf 455 ho. Still has the correct carb and dual snorkal air cleaner. Im still soaking mine , but at least is still has antifreeze in it sitting all these years. Hope it doesnt need much either.

[Will]

All sounds good except I'd REALLY REALLY REALLY encourage you to go bigger on the cam. A 455 will soak up a lot more cam than a 400 will, so comparing a poor running 400 with a good sized cam to a 455 with the same cam isn't really possible.

If you want to stay conservative on the cam for a mild driver that 2802 would be a great choice. The 068 is a real pussycat of a cam even in a 400. It'll idle dead smooth and have massive low end torque in a 455 but be out of breath fairly quickly. The 2802 would give a lot more midrange punch and still be nice and docile in that engine. Some Crower 68404 springs will drop right in under the stock spring retainers with stock valves and handle that cam fine though you should check retainer-seal clearance. Might have to have the guide bosses machined for a bit more clearance but then you'll be able to use the good viton seals.

Anyway, that's what I'd do if I was in your shoes. Good luck and have fun whatever you do!

[Jay S]

I helped a friend with a 455HO here last summer in a 70 GTO with 3.07 gears, speed pro pistons, it was running the melling 068 with 1.65s and RA manifolds. Which sounds like the same direction this engine is going. Someone OH’d the engine previously but balanced the crank wrong and drilled through an oil galley on the crank. The engine lost oil pressure and had to be rebuilt again. He thought it had close to 9.8 compression. I helped him measure cc every thing, with the flat top forged speedpros the compression was 9.28:1. So check those specs, his heads were 92-93 CC and the deck my friends 70 455 HO was the tallest I have ever seen for a Pontiac block. You may have to have some decking done to keep the compression in the 9s with much of a dished piston. The 068 with 1.65s seems to be a nice running stock type cam in 8.5-9.5:1 455. I would rather run it closer to 9 with the cam advanced a bit if you don’t want to do much tuning for pump gas.