[fixitrht]

Hi folks , I came across a 70 WA block which looks to be. 455 4 speed. However, when I look up engine codes I see 2 455’s fir that year with a 10hp difference. Is that difference representing HO? Really just trying to figure out what I have and who best may be able to use it. Is this a base 4 speed GTO? I don’t see round 1970 port cars. Thanks

[johnta1]

No round port 455's in 1970.
The HP rating is probably advertising 'gimmicks'?
Could be with the use of the Ram Air hood, they added the 10 HP to the rating. Engine-wise it's the same.

[unruhjonny]

There were, as John mentioned, no round port 455's in 1970;
There was though a D-port '455HO' in 1970.

There was also a numbers game being played with advertised 455 hp figures, as the GP got a higher hp rating than the GTO, even though the GTO 455 was the HO;
I believe that this was because the GP weighed more.
(observed in 'performance catalogue')

I opened up some literature before hitting "reply" here, and based on camshaft specs, it reads as though the GTO always received the 455HO, while the GP & full sized received the regular;
What's confusing to me is that in the performance catalogue, the GP shows the 067 cam (which would denote the non-HO motor), while the GTO shows the 068 cams (which would denote the HO motor);
But then the McCarthy book shows that the s/t engines received the 068, while the a/t engines received the 067 cam.

I also get confused with the 'Ram Air' option on the GTO, as to which engine received the RA exhaust manifolds - because I though the HO always received the RA manifolds.

I did have this straight in my head though:
7040262 = non-HO/at
7040267 = 455HO/st
7040268 = 455HO/at

[steve v]

What are the last 4 digits on the vin? I've got 2 455 cars that lost their original engines many years ago. Thanks!

[fixitrht]

Grey information folks , thanks for the education. I’ll look t the digits and let you know

[scott70]

1970 455 with #15 heads with small valves and pressed in studs. 70 455 ho,,,#64 heads with big valves and screw in studs. WA block equals 4 bolt mains. M/t got 068 cam,,,autos got 067. So a manual trans 455 ho was the highest HP of the different 455 combos. They did rate the same motor in a GP as 10hp more but theres no difference in the engines. They didnt detune the engine for the gto or put limitations on the secondaries like the firebird 400. A good WA block is desireable. 70 455 ram air cars did not get the ram air manifolds.

[Baron Von Zeppelin]

Originally Posted by fixitrht

Hi folks , I came across a 70 WA block which looks to be. 455 4 speed. However, when I look up engine codes I see 2 455’s fir that year with a 10hp difference.

There were 2 different 455's in 1970 , and those 2 came with different Heads.
Fullsize Cars could get the standard 455 with #15 Heads or the 455 HO with #64 Heads. In a Fullsize car with Automatic - the base 455 was code YC - the 455 HO was code XF (XF code also used in GPrix)

GPrix and GTO all got the 455 HO with #64 Heads
It was the only 455 available in them.
70 455 HO GTO with RamAir didn't increase Horse Rating

WA could have been 3spd M13 or 4spd M21
But GTO Only for the WA code.

No R/A exhaust manifolds with 455 HO/RamAir in 1970
It was only an Induction Package , but did include R/A Carb

['ol Pinion head]

Todd, the YC code was not the base 455 in a '70 Pontiac B series it was the YH coded 455. Have pulled a ton of '70 Bonne 455 YH engines, most had two bolt main caps, but 3 or 4 had factory 4 bolt main caps. Pontiac built over 100,000 '70 Bonnevilles, & their 455's were a fairly easy find in the late 80's up through the mid 90's.

[Baron Von Zeppelin]

You're exactly right - it was YH / 15

YA / YC was early & late GTO 455HO with Automatic

Don't know how i didn't catch myself on that one. Thanks Roger !

[69hardtop]

Originally Posted by steve v

What are the last 4 digits on the vin? I've got 2 455 cars that lost their original engines many years ago. Thanks!

I found my WA engine in a barn just North of Detroit late last year. Here is VIN.....you never know.

[johnta1]

Could you post the engine unit number (below the engine code) and cast date also?
(for my eun database)

[69hardtop]

Originally Posted by johnta1

Could you post the engine unit number (below the engine code) and cast date also?
(for my eun database)

Here is mine....date code is K249

[johnta1]

Thanks!

[68WarDog]

Originally Posted by steve v

What are the last 4 digits on the vin? I've got 2 455 cars that lost their original engines many years ago. Thanks!

Steve, I recently junked a WA 455 block here in Salisbury after discovering cracks in the saddle. I was however able to salvage the crank, 4 bolt main caps and 1099 # 64 heads.

[fixitrht]

0171708
WA
1259
9799140
Funny vin is stamped almost 3 times
00 and 01 is stamped just below but looks hot twice

[steve v]

Originally Posted by fixitrht

0171708
WA
1259
9799140
Funny vin is stamped almost 3 times
00 and 01 is stamped just below but looks hot twice

Well it's not from either of my cars. I knew it was a longshot at best but I had to ask.
I do have a WA from a Freemont built car & it was stamped twice up high on the pass side front....they did things like that in CA I've been told.
Thanks for checking!

[FrankieT/A]

There was no "HO" in '70 technically. Simply said, you had the performance 455's with 64 heads and big car 455's with 15's.

[Baron Von Zeppelin]

What is the technical limitation of them not being 455-HO in 1970 ?
Better carb, better heads, 4 bolt mains, 12 Bolt Rears

There were also 326-HO and 350-HO engines in prior years.

In 1975 there was a fluke 455-HO available in Trans Am.
With no physical departure from the 455 in a Fullsize

[Baron Von Zeppelin]

Originally Posted by Baron Von Zeppelin

Better carb, better heads, 4 bolt mains, 12 Bolt Rears

500 ft lbs Torque
mightiest of all the PMD's @ torque value
Forgot about that one

They call it 455-HO on all the Invoices, Window Stickers and Buildsheets
close enough for me i guess

[unruhjonny]

Originally Posted by Baron Von Zeppelin

In 1975 there was a fluke 455-HO available in Trans Am.
With no physical departure from the 455 in a Fullsize

The difference being that the 1975 "455 HO" was an option package, as opposed to an engine;
The confusion was enough that when carried over into 1976 the "HO" was dropped.