[Doug1]

I pulled the 1970 455 HO from my 79 TA yesterday. The stock oil pan wasn't holding enough oil during hard accelleration, particularly right hand turns. Also had a lifter that would occassionally tap so I figured I just pull the motor out and check it out.

The build has 1500 miles on it. The block is 30 over 1970 HO 4 bolt 455. It has a lifter bore brace fitted, oliver rods, forged pistons. Really good shape. I pulled the e heads and am most likely going to have them ported and upgraded as they are out of the box heads.

I also have a 2nd block that I put together with an Eagle crank, rods and Ross pistons. A complete balanced rotating assembly from SD Performance. It is in a 76 455 block with 2 bolt mains that were installed using factory bolts. I had a set of KRE 290s to go with it but decided to go bigger and Dave from SD is trading those back in towards the new motor. That motor is a IA2 700hp motor I just bought for my long term keeper project I am building. In the meantime, I need to put a motor back in the blue TA that I will likely sell at some point in the next few years.

So my question is this... The 76 shortblock has never had a set of heads on it. the 70 HO motor has only 1500 miles on it. I think both would hold up to the 600 HP I plan for in this small upgrade. So would it be worth a lot more money to get rid of the HO block since it is more of a collector item than the 76?

Will the 70 HO block bring a lot more money than the 76? If there is only a few hundred dollars difference then I'll keep the HO block. If it is worth considerable money to some dude who wants a 1970 HO motor to have a correct restoration, then I would let it go.

[Tom Vaught]

1) 1970 was the first year for the 455 engine. The "455 HO" engine was really nothing special except for the fact that it was 455 CID. The heads were normal heads with the 2.11 /1.77 valves and 87cc combustion chambers. Basically a "D-Port" head engine with the largest production cubic inch displacement that year but offered now in the 1970 Trans Am.

2) 1976 455 Engine was the last year of the 455 cid offered in the Pontiac line. Again, nothing special.

Either engine in my mind would fetch the same money IF you found a 70 TA guy or a 76 TA guy with some money and a need for an engine. The "resto boys" are going to want the exact engine (based on build sequence numbers) for their application.

The 70 engine might be a bit stronger for a performance application (cylinder walls, web structure, etc). Both should be basic 2 bolt main stuff.

Tom Vaught

[ANDYA]

Due to the 4-bolt main, Oliver rods and lifter bore brace I would keep the 70 HO block and sell the other one. Hold onto it, you never know when you might need it for a future project.

[Doug1]

Tom,

That is kind of what I was thinking. Other than the 4 bolt mains on the 70, there is not much difference. Particularly when staying under 700hp.

That is why I was trying to figure out if the HO 4 bolt was worth more money. Either will work for me.

Andya,

Agreed that if there is no real difference in value, as in thousands of dollars, then I'll just keep the 70 block. It is already been used so if the block isn't worth a bunch more money, then the newly rebuilt block will probably fetch the same or better.

I ended up with an extra short block because I traded the KRE's back to Dave. I still have them but am getting ready to ship them this week. I never installed them so they are exactly as they walked in the door.


Tom,

Once I figure out how to get some boost and keep it under a shaker, I am going to make that my next build. ;-) Already have more horsepower than I can use on the street but this stuff is addictive. NEVER enough power!

[Tom Vaught]

Doug, I am personally not a big fan of 3.25" main "4-Bolt" main cap blocks for boosted applications. I think the outer bolt holes actually weaken the blocks to some extent. Caps may or may not be stronger.

If it is a 70 block at least you will be able to experiment with the block and prove me wrong when you go boosted. LOL!

Tom Vaught

[riskey69]

HOW MUCH WOULD YOU WANT FOR THE 1970 455?

[Doug1]

I just sold the other block this weekend. Once the money is here, I will be shipping it so I will be keeping the 70 block.

[azbirds]

Originally Posted by Tom Vaught

1) Basically a "D-Port" head engine with the largest production cubic inch displacement that year but offered now in the 1970 Trans Am.


Tom Vaught

Wow Tom, this is the first time I have to disagree with you. The T/A didn't get a 455 until 71 and it was a real HO. The 70 HO was indeed a d-port, but it came in the Goat. I had one of those blocks and it went for a lot of money. I can't remember how much it sold for though.

[Slick]

azbirds is correct.

Scary to disagree with Tom who is very knowledgeable, but the 70 T/A was only available with 400s. [Even a Pontiac advertisement a few years later made that mistake]. The 1970 standard 455 had 1.96/1.66 valves and press-in studs (#15 cylinder head). Mine ran fantastic. But, the 1970 455"HO" with #64 heads had slightly higher compression, 0.25 point if I remember correctly, 2.11/1.77 valves and screw-in studs. So there was a little difference. May have come with a different cam other than the "P" cam, but I'd have to look that one up.

Stuart

[Tom Vaught]

Originally Posted by Slick

azbirds is correct.

Scary to disagree with Tom who is very knowledgeable, but the 70 T/A was only available with 400s. [Even a Pontiac advertisement a few years later made that mistake]. The 1970 standard 455 had 1.96/1.66 valves and press-in studs (#15 cylinder head). Mine ran fantastic. But, the 1970 455"HO" with #64 heads had slightly higher compression, 0.25 point if I remember correctly, 2.11/1.77 valves and screw-in studs. So there was a little difference. May have come with a different cam other than the "P" cam, but I'd have to look that one up.

Stuart

1) I do not consider .25 more compression, significant.

2) I do not consider 2.11/1.77 valves and screw-in studs, significant. All 4 bbl heads were basically screw-in studs with the larger valves.

3) People have installed 421 engines in 64 GTOs, 428 Engines in 1968 400 Firebirds,
and 70 455 4 bbl engines in 1970 400 Trans Ams.

4) The 70 455 HO engine was nothing special, no round port heads, I believe the engine did not have 4 bolt main caps installed. The difference being a larger cubic inch engine.

5) 1971-1972 455 HO engines WERE different.

I guess it depends on your viewpoint.

Sorry for the confusion.

Tom Vaught

[azbirds]

Hey Tom, I'm not busting your chops over this because I know your vast knowledge. I was jst surprised. Just as a side note, my 70 455 HO block does have the factory 4 bolt cap on it. How about others out there?

[performerrpm]

Originally Posted by Tom Vaught

1) I do not consider .25 more compression, significant.

2) I do not consider 2.11/1.77 valves and screw-in studs, significant. All 4 bbl heads were basically screw-in studs with the larger valves.

3) People have installed 421 engines in 64 GTOs, 428 Engines in 1968 400 Firebirds,
and 70 455 4 bbl engines in 1970 400 Trans Ams.

4) The 70 455 HO engine was nothing special, no round port heads, I believe the engine did not have 4 bolt main caps installed. The difference being a larger cubic inch engine.

5) 1971-1972 455 HO engines WERE different.

I guess it depends on your viewpoint.

Sorry for the confusion.

Tom Vaught

wow, i was expecting something along the lines oh my mistake,

[Doug1]

It does have 4 bolt mains. I have it in the garage now and can take any pics ya'll might want to see. It is sitting right next to my brand new 535 that came in yesterday. (Not that the 535 is relevant but I figured I woudl throw that in because I am one happy camper! )

[Slick]

2) I do not consider 2.11/1.77 valves and screw-in studs, significant. All 4 bbl heads were basically screw-in studs with the larger valves.

3) People have installed 421 engines in 64 GTOs, 428 Engines in 1968 400 Firebirds,
and 70 455 4 bbl engines in 1970 400 Trans Ams.

4) The 70 455 HO engine was nothing special, no round port heads, I believe the engine did not have 4 bolt main caps installed. The difference being a larger cubic inch engine.

Tom,

I do take issue with the statement that All 4 bbl heads were basically screw-in studs with larger valves. The #15 heads, as mentioned earlier, with small valves and press-in studs were stock on my 1970 Bonneville 4 bbl, dual exhaust, 3.23 rear, 29" tire car. It was no pig. Completely stock it was slightly faster than my 1970 Trans Am Ram Air III automatic 3.31 rear car. 14.31 @ 99.5 for the T/A, 14.15 @ 97 for the Bonny. I bought it from Bob Maxey, it was his wife's car. He told me that when you could get Sunoco 260, you could run the timing at 34-36* and he felt the car was possibly high 13's. But even when I had it in the 80's, 93 octane only let me run 30* total. So even those heads can work in the right combination.

The 1971 standard B body 455 4 bbl had the larger valves, but still the press-in studs (#66 heads), but they seem to flow as well on the exhaust side as the same year HO heads according to that old Pontiac head comparison test from HPP (I think).

There may be others, I'm not sure.

I know that people installed and continue to install a variety of engines in Pontiacs, Trans Ams and otherwise. My point was that the factory did not offer a 455 in a 1970-1/2 Trans Am; special or otherwise.

Your point #4 is a bit confusing: "The difference being a larger cubic inch engine". Huh?
Larger than a 1969 428 as in a 1969 B body or G body? Larger than a 400, as in a 1969 A body or F body? Don't see where the previous year engine sizes come into play. Since we were comparing 455 standard vs. HO, the larger cubic inch comment was a bit confusing.

Whether a 1970 455HO engine is special or not, it is a bit different from the baseline 455. It may not run better, though. Personally, I do consider screw-in studs and the bigger valves significant.

Stuart

[performerrpm]

wonder why they even bothered with the larger valves and screw in studs?

[Tom Vaught]

Slick;3996516]

I do take issue with the statement that All 4 bbl heads were basically screw-in studs with larger valves. The #15 heads, as mentioned earlier, with small valves and press-in studs were stock on my 1970 Bonneville 4 bbl, dual exhaust, 3.23 rear, 29" tire car. It was no pig. Completely stock it was slightly faster than my 1970 Trans Am Ram Air III automatic 3.31 rear car. 14.31 @ 99.5 for the T/A, 14.15 @ 97 for the Bonny. I bought it from Bob Maxey, it was his wife's car. He told me that when you could get Sunoco 260, you could run the timing at 34-36* and he felt the car was possibly high 13's. But even when I had it in the 80's, 93 octane only let me run 30* total. So even those heads can work in the right combination.

The 1971 standard B body 455 4 bbl had the larger valves, but still the press-in studs (#66 heads), but they seem to flow as well on the exhaust side as the same year HO heads according to that old Pontiac head comparison test from HPP (I think).

There may be others, I'm not sure. Stuart[/QUOTE]

Stuart, This topic is a lot like Pete McCarthy's book: Pete made general statements and was immediately hammered by every "exception" Pontiac ever built to the basic plan. "My
326 4 bbl engine had press-in studs and small valves."

Another "General Statement" All Basic Cast Iron Traditional Pontiac Production Heads" flow about the same numbers. This is a true statement. Years ago people would actually take off their perfectly good casting Number #16 heads heads and swap then for "RAM AIR" #48 heads and some cash! They did not have a Ram Air Correct Engine. They thought they were getting better flowing parts.

Same deal with the screw-in studs deal. Most press-in stud heads will go 100,000 miles or more with never a stud getting loose or requiring any maint. Screw-in studs for the most part were not needed. Same deal with the 1.77" exhaust valves vs the 1.66" valves. LOT OF PEOPLE HAVE GONE VERY FAST WITH NO MORE THAN A 1.71" DIAMETER VALVE.

Everyone talks about the vast engineering knowledge at Pontiac and yet in some cases you have to wonder about the parts being driven by advertising vs engineering.

The 1971-72 455 HO engines and the 455 SD engines (as well as the RA-V/ NASCAR 366 engines being the exception.

The BASIC Engines were WEAK when pushed to racing requirements. Everyone knows the cast cranks will fail eventually, the rods will fail eventually, the blocks will fail eventually.
We have much better parts today than years ago BUT the STOCK Traditional Pontiac Engine did what it was designed to do: Flow a given amount of air, make a given torque, run a given rpm, live a certain number of miles. All of the parts are basically the same since 1959: 389 thru 455 engine.

Slick;3996516]

"I know that people installed and continue to install a variety of engines in Pontiacs, Trans Ams and otherwise. My point was that the factory did not offer a 455 in a 1970-1/2 Trans Am; special or otherwise."[/QUOTE]

My point was (and others added to it that some of the 70 455 blocks were 4 bolt main.)
If a 70 TA guy wants a 1970 4 bolt main block engine in his car, he will be interested in the engine and may even buy it. Same deal for the 76 Engine with a 76 Owner.

The man was asking which engine would bring more money. I said they both were "basically the same". I would not pay a dime difference in either one personally.

Slick;3996516]

Your point #4 is a bit confusing: "The difference being a larger cubic inch engine". Huh?
Larger than a 1969 428 as in a 1969 B body or G body? Larger than a 400, as in a 1969 A body or F body? Don't see where the previous year engine sizes come into play. Since we were comparing 455 standard vs. HO, the larger cubic inch comment was a bit confusing.

Whether a 1970 455HO engine is special or not, it is a bit different from the baseline 455. It may not run better, though. Personally, I do consider screw-in studs and the bigger valves significant.

Stuart[/QUOTE]

Everyone has his right to his opinion Stuart. I gave mine, see above.

Tom Vaught

[61-63]

Some people just cannot admit making a mistake or being wrong.

[Doug1]

To finalize the thread... I pulled the 70 4 bolt, stored it, sold the 76 shortblock this past week and just got this on Wed... IA2 535 built by SD Performance.

Slightly more horsepower than stock at 720 :-)

[Tom Vaught]

Originally Posted by 61-63

Some people just cannot admit making a mistake or being wrong.

I make LOTS of MISTAKES. Why should I have to Kiss your Butt when I explained my position in the previous post? How about this, you "post the answers" for a while and I will keep MY OPINION of the parts capability to myself.

Tom Vaught

[Tom Vaught]

Quote from GOQUICK:

Originally Posted by goquick

The iron head d-port castings are all too close to pick a certain number to look for. I look for core shift issues more than caring about what casting number is on it. I've done the trading one casting for another because x is supposed to be better than y and my experience was i did alot of work for nothing. Only time I started noticing any performance difference ( and backed up with vists to the dragstriip) was when I could see core shift vs. very little or no core shift. Even then it wasn't even a tenth difference.

Tom Vaught