[FrankieT/A]

I have always wanted a really big cubic inch motor that was just over sized. Meaning normal idle, normal driving characteristics but like 500 cubes. That wasn't really realistic back in the day. Other old guys(like me) can tell you that you couldn't just go in a catalog or online and buy a stroker crank like you can today. Things were not made in China like today. You want a stroker crank? You have to go to Moldex or Hank The Crank for a seriously expensive crank (about $3000.00). Oh, did you want rods for that? Another $1500..00 in 1970's dollars for that. Oh wait we're gonna need pistons, custom Venolia? Cha Ching!!! And this is Chevy stuff. Pontiac, Olds, Buick you need a loan application. To get a stroker kit today, what? 17-1800.00 bucks? Crank, rods, pistons, bearings, rings...at your door in a week. You get the point. Large cube engines are almost commonplace these days.

Like others have said in this thread "I like an over square engine" My retirement engine might be a 455 .030 block with 428 4" crank and some serious flowing E heads.

[Douglas Willinger]

Originally Posted by 72LuxuryLeMansLa.

Doug,
The link brings me to the log on page.... Guidance to find the thread?

Go to " Restoration & Performance Forum"

page 3

1970 Ram Air III/IV 434 Build
1 2 3 4

start of thread http://psp.aquacomp.net/topic.asp?TOPIC_ID=13682

The most recent post is July 26, 2018

[footjoy]

Like others have said in this thread "I like an over square engine" My retirement engine might be a 455 .030 block with 428 4" crank and some serious flowing E heads.

What is an over square engine?

Thanks

Greg

[b-man]

Originally Posted by footjoy

Like others have said in this thread "I like an over square engine" My retirement engine might be a 455 .030 block with 428 4" crank and some serious flowing E heads.

What is an over square engine?

Thanks

Greg

Over square - bore dimension bigger than stroke, all Pontiac V8 engines fit this description with the exception of the 326 and 455.

Under square - stroke dimension bigger than bore

Square - both the bore and stroke dimensions are equal

The 455 only needs to be bored approximately +.060” to become ‘square’ (4.210” x 4.210”).

Same thing goes for the 326 with the factory 3.72” bore and 3.75” stroke but only needs to go +.030 over bore to be square. Funny that in 1963 which was the very first year of 326 production the bore was actually 3.76” for some reason and was then reduced to 3.72” for 1964 through the end of production in 1967. Great little V8 which might be the one with the highest reliability and longevity of all Pontiac V8s.

Both of these slightly under square Pontiac engine offerings are excellent street engines for their intended purposes, neither one should be overlooked when either big torque in the case of the 455 or excellent economy in the case of the 326 is desired.

Some here might be surprised to learn that many if not most of the big-cube Pontiac race and street engines are under square. With bore sizes under 4.40” for most and strokes 4.50” and larger Pontiac engines don’t necessarily need to be over square to be great racing or street engines.

[FrankieT/A]

I had my first Pontiac when I was 16. It was a 1970 Catalina Convertible with a 400 2BBL. I wasn't into "Pontiac" per se, I was happy to drive anything. My first foray was when I bought my current 1978 T/A which I bought new. Point of the story is, I met an old guy ready to retire that was a mechanic in the service dept. If he is still with us he's got to be a 105 by now. Yes, "mechanic" not "technician". Anyway, he said something to me that always stuck.

"Pontiacs are designed for torque, build for it..."

Thanks Jesse where ever you are...

[72LuxuryLeMansLa.]

Originally Posted by FrankieT/A

I had my first Pontiac when I was 16. It was a 1970 Catalina Convertible with a 400 2BBL. I wasn't into "Pontiac" per se, I was happy to drive anything. My first foray was when I bought my current 1978 T/A which I bought new. Point of the story is, I met an old guy ready to retire that was a mechanic in the service dept. If he is still with us he's got to be a 105 by now. Yes, "mechanic" not "technician". Anyway, he said something to me that always stuck.

"Pontiacs are designed for torque, build for it..."

Thanks Jesse where ever you are...

Youz A Lucky som$$$$$! My first car was a weak azz 4cyl. chevy luv....

[goatwgn]

Originally Posted by b-man

Over square - bore dimension bigger than stroke, all Pontiac V8 engines fit this description with the exception of the 326 and 455.

Under square - stroke dimension bigger than bore

Square - both the bore and stroke dimensions are equal

The 455 only needs to be bored approximately +.060” to become ‘square’ (4.210” x 4.210”).

Same thing goes for the 326 with the factory 3.72” bore and 3.75” stroke but only needs to go +.030 over bore to be square. Funny that in 1963 which was the very first year of 326 production the bore was actually 3.76” for some reason and was then reduced to 3.72” for 1964 through the end of production in 1967. Great little V8 which might be the one with the highest reliability and longevity of all Pontiac V8s.

Both of these slightly under square Pontiac engine offerings are excellent street engines for their intended purposes, neither one should be overlooked when either big torque in the case of the 455 or excellent economy in the case of the 326 is desired.

Some here might be surprised to learn that many if not most of the big-cube Pontiac race and street engines are under square. With bore sizes under 4.40” for most and strokes 4.50” and larger Pontiac engines don’t necessarily need to be over square to be great racing or street engines.

I agree on the longevity of the 326. My '66 326 2 bbl went pretty trouble free for 292000 miles, when I pulled it (still running well, but a bit weak) in the late 1980s for a 455, which in itself went 100000 miles, of hard use, and the only reason I pulled it to redo it in 2011 was to reduce the compression to be able to run it trouble free on low octane gas. I was running the old 10.5 to 1 engine with a mild cam with dialed back timing, and octane boosters.

[NeighborsComplaint]

In stock form, It lacked the RPM potential of the 400 and the low end torque of the 455. Also, the longer stoke of the 455 made it more emissions friendly.

[U47]

Originally Posted by MarkS57

Olds was already at 455, Ford at 460 & Chrysler at 440 before 1970, so in 70, Buick went 430 to 455, Chevy 427 to 454, and Pontiac 428 to 455. My recollections of the 428 were memorable too. Courtesy of a Bonneville that would happily chirp its 1st to 2nd shift when mashing the loud pedal.

I think the above sums up the idea very well. A matter of everyone getting on the bandwagon for bragging rights. Besides the 428 wasn't a 428 anyway, it was a 426 and change, Being a 426 and change meant that Pontiac could still run NASCAR at that period of time, also NHRA if it wanted to. .
As for the 428, it's got a better B/S ratio than a 455, and a 455 when run at extended high load like road racing there is just too much piston speed that creates heat, a lot of heat.
I wish Pontiac would have increased it's bore spacing so that it could reduce it's stroke to no more than 3.75, and even 3.75 had problems going the distance sometimes.
As for the heavy car like Grandville on the street, the 455 is a great engine.

[Schurkey]

The four divisions of GM had four entirely different engine families, all of them labeled as 454 or 455.

Coincidence?

I bet there was a GM dictate that limited all but Cadillac to a maximum displacement; and it happened to be "under 456" cid.

Given the wider bore centers of the Buick and Chevrolet engines, there's no reason to think they'd have self-limited to the same general displacement as Pontiac and Olds otherwise.

[bobzdar]

A 3" main 4" stroke would have been ideal given the bore limitations of the block, a 455 with it's higher bearing speeds and higher piston side loading due to the rod/stroke ratio is under more bottom end stress than a 400 at similar power levels despite the 400 having to rev 14% higher. Valvetrain is under less stress, but I'd generally rather run into valvetrain issues than bottom end issues. But the cars got bigger and heavier, emissions got tougher to pass at idle, and a 455 at 800rpm idle is tolerant of a little larger camshaft and can move a 5000lb boat with freeway gears more easily, so they had to make some sacrifices.

[mgarblik]

Originally Posted by Schurkey

The four divisions of GM had four entirely different engine families, all of them labeled as 454 or 455.

Coincidence?

I bet there was a GM dictate that limited all but Cadillac to a maximum displacement; and it happened to be "under 456" cid.

Given the wider bore centers of the Buick and Chevrolet engines, there's no reason to think they'd have self-limited to the same general displacement as Pontiac and Olds otherwise.

I have no proof but also no doubt that some sort of internal rule did exist. Pontiac as a single division, always seemed to end up on the short end of every internal rule. Early on, it may have been their general dislike for John Deloreon. Later as he carefully, defied the rules and Pontiac sales went through the roof, pressure from the "cheap crap" division, Chevy further hampered Pontiac and kept them under the thumb of Chevy. Cadillac had bigger, heavier, more expensive cars, and displacement was king. It makes sense they should have the largest engines.

[242177P]

Originally Posted by Schurkey

I bet there was a GM dictate ...

There must have been, and it got lifted (somewhat) for 1970.

A-bodies were limited to 330 CID.
Buick 300
Pontiac 326
Chevy 327
Olds 330

But Pontiac found a loophole. New limit, 400 cubes.
Pontiac 389/400
Chevy 396/402
Olds 400
Buick 401/400

And the big cars were limited to 7 liters (aka 427 CID)
Pontiac 421/428
Chevy 427
Olds 425
Buick 430

And there was also a corporate edict, no more than 1 hp/10 lbs.
I believe that GM had to struggle to keep their divisions in line.

[Formulas]

I love the post saying the 428 lacked RPM over the 400 and lacked torque over 455.

You could also say the 400 lacked torque of the 428 and the 455 lacked RPM of the 428

I find the near linear torque of the 455 boring
And I find the lack of low end 400 torque boring
I find the 428 to be a decent mix of both 400 and 455 engines in a apple's to apple's comparison

As far as the 428 demise it most likely had to do with marketing and bean counting at the time they for whatever reason didn't like to put them in the smaller cars and they had to have a 455 for the larger cars to keep up with marketing and the Jones's

[ramairthreegto]

Originally Posted by TheGrudge

I think that 390hp 428 may have been a little overrated, or the 360hp GTO 455 engine was underrated.

There’s no way the ‘70 455 GTO was the dog it was made out to be.

One of those #64 head 455's, with no change except an 041 clone cam/Rhoads lifters, ran 12.40's in my '68 Bird bracket car. The Bird had 3.55 gears & a stock 13" converter [/QUOTE]

....and right there; ‘70 GTO 455, had it been offered as a RAIV would have been up there with LS6 and Stage 1 (at least in stock form). Shame that.[/QUOTE]

I have never had a Pontiac 428.

I had a junkyard 455 in my 69 GTO in the 80s.
And I have the original one in my 70 GTO.

If it had been done right, the 70 455 could have been the stuff of legends like an LS6, Hemi, 440 six pack, Buick, or Olds or SCJ of that year.

It was not.

But I do think that engine is under appreciated by most.

It crushes my RAIII 400.

And it is way more fun to daily drive than a RAIV 400 and I do believe with the same transmission and rear end will tie it in the quarter.

[steve25]

My wish is that the 428 would have been kept in production into 1970 and been offered up in the A body cars with the RA4 Cam at least in the same way Pontiac did with the late 1968 RAII motor.

A 12 bolt rear should have been part of the package also!

[goatwgn]

Originally Posted by bobzdar

A 3" main 4" stroke would have been ideal given the bore limitations of the block, a 455 with it's higher bearing speeds and higher piston side loading due to the rod/stroke ratio is under more bottom end stress than a 400 at similar power levels despite the 400 having to rev 14% higher. Valvetrain is under less stress, but I'd generally rather run into valvetrain issues than bottom end issues. But the cars got bigger and heavier, emissions got tougher to pass at idle, and a 455 at 800rpm idle is tolerant of a little larger camshaft and can move a 5000lb boat with freeway gears more easily, so they had to make some sacrifices.

This is exactly why Cadillac went to 472/500. Ideal for moving giant beasts, at low rpm, with mid 2 series axle ratios. For their displacement and weight, they got pretty acceptable fuel mileage as well. The large displacement and heavy weight, along with the gearing, ensured a very relaxed highway ride, all day long.

[goatwgn]

How about the 455 block, fitted with a 428/421 crank, and correct pin height pistons?

[bobzdar]

Originally Posted by goatwgn

How about the 455 block, fitted with a 428/421 crank, and correct pin height pistons?

455 block with 428 crank is just an .030 over 428 (or .060 over 421) for 434 inches.

[MarkS57]

Originally Posted by steve25

My wish is that the 428 would have been kept in production into 1970 and been offered up in the A body cars with the RA4 Cam at least in the same way Pontiac did with the late 1968 RAII motor.

A 12 bolt rear should have been part of the package also!

Yup, call it a 428 Super Duty. Given Pontiac's talent for skirting the rules, a 428 SD Formula Firebird would have been insane ..oh well...