[TRADERMIKE 2012]

By the way I was pleased to learn that the Crank Caps are formed as one and then split then line Bored and that is why Caps only fit one particular Block. How smart is that? That, is why you Engineers make the Bucks $$$$ Keep the info. coming.

Tekuhn, By the way your Tempest is so cool but I must say, that Half Motor would be in the Museum in the House and that V-8 Block Cosmoline would be installed, so fast, before you could think about it, if it were up to me...However I respect what you're doing." I know you must have thought about it ". Also, I see that set -up topped in Tri-Power. Mike out.

[tekuhn]

Originally Posted by TRADERMIKE 2012

.......Tekuhn, By the way your Tempest is so cool but I must say, that Half Motor would be in the Museum in the House and that V-8 Block Cosmoline would be installed, so fast, before you could think about it, if it were up to me...However I respect what you're doing." I know you must have thought about it ". Also, I see that set -up topped in Tri-Power. Mike out.

I can't justify using that particular block, but I do have a 428 that will reside there, hopefully sooner than later. It will have 614 heads and dual quads.

[TRADERMIKE 2012]

That will work even better, make it a Super Duty Clone. I wanted to know if there is the Rope Drive type Drive Shaft in your Tempest. I read about one some time ago and it gave more floor space between the driver and passenger floor since the Rear Transaxle and Independent suspension were like the Corvair.

[tekuhn]

Originally Posted by TRADERMIKE 2012

That will work even better, make it a Super Duty Clone. I wanted to know if there is the Rope Drive type Drive Shaft in your Tempest. I read about one some time ago and it gave more floor space between the driver and passenger floor since the Rear Transaxle and Independent suspension were like the Corvair.

Yes, it currently has the stock drivetrain with the 3/4” chrome moly driveshaft and 3-speed transaxle. With the V8 conversion, I plan to install a Tremec TKO600 transmission and a rear IRS subframe.

[Rocky Rotella]

Originally Posted by tekuhn

I'm not sure how I feel about this information. I thought I was buying a RA-IV SR block. It has the correct RA-IV block part number with an A added, yet it's clear it was intended for replacement of a RA-III with 4-bolt main caps. There is no difference in the block, only the pistons that were fitted to it. Does this information diminish the value of the block somewhat? Is a "B" block worth more than an "A" block if they were in identical condition? Could someone restoring a '70 RA-IV vehicle use this block and it be considered correct? With what I now know, I would have to say no.

I realize this is all subjective, and I didn't buy the block as an investment. I bought it to pair with a set of 614 heads for a '70 Judge I was building. After I bought the WY RA-V crate engine for the Judge, I stopped any plans to build the RA-IV. I no longer have the Judge or the RA-V engine.

I don't know that I'd be too concerned with the situation. Whoever would potentially buy the block for their vehicle is buying it for the stamped part number and not necessarily the pistons. In fact, with the way things are today concerning aftermarket parts availability (with COVID) notwithstanding, from a performance standpoint there are much better piston options than what Pontiac developed 60+ years ago.

Where the "real" application is concerned, I believe that it being for a Ram Air III actually increases your potential buyer base. Based on the stamped casting number, the block is the correct SR unit for any 1970 R/A III or R/A IV and that's what most people are concerned with. I don't think anyone but those that reads this particular post (and believes me!) will have any idea what the A/B means. And it was limited to the 1973 castings as best as I can tell so far.

In the end, no matter how you look at it, you still have an NOS 9799915 SR block!

[tekuhn]

Thanks, Rocky. BTW, the block was missing two pistons when I bought it, so the pistons themselves add no value to it. In fact, I removed the remaining six and they are long gone.

[Rocky Rotella]

Well, that took care of itself!

[TRADERMIKE 2012]

Tekuhn, NOW THAT I KNOW HOW ORIGINAL THAT Tempest IS, I HAVE TO RETRACT MY STATEMENT AND SAY YOU NAILED IT THE WAY IT IS, PUT THE EXTRA GOODIES TOWARD THE 1965 PROJECT. The Tempest IS WAY TO COOL AND UNIQUE, ONE OF A KIND TO BASTERDIZE. Sorry, about the caps lock again. Mike out.

[SD455DJ]

Originally Posted by Tellyshavilli

On the service replacement (9792506 ) 400 ra blocks the factory ground off one of the engine mount bosses so that would not be able to be used in a 70 up application very strange but I’ve seen many like this

I also have a SR 9792506 400 block that has the driver side engine mount boss ground off like grandam1979's. It's casting date is B222 and the block p/n is completely ground off and stamped. The number is SR88044.

Dennis

[tekuhn]

Originally Posted by TRADERMIKE 2012

Tekuhn, NOW THAT I KNOW HOW ORIGINAL THAT Tempest IS, I HAVE TO RETRACT MY STATEMENT AND SAY YOU NAILED IT THE WAY IT IS, PUT THE EXTRA GOODIES TOWARD THE 1965 PROJECT. The Tempest IS WAY TO COOL AND UNIQUE, ONE OF A KIND TO BASTERDIZE. Sorry, about the caps lock again. Mike out.

I love the looks of the car, and the engine runs very well, but it’s just too underpowered. The clutch is garbage and the driveshaft needs bearings. It needs to be fun to drive, so V8 it will be. Also the suspension needs to be modernized. I’m building a Mustang II crossmember and front suspension with coil-overs and power rack and pinion. The rear suspension will be a complete subframe from a Nissan 300ZX Twin Turbo. The diff is perfect with 3.69 gears and over a 9” ring gear with viscous limited slip. It’s very stout and looks to be an excellent fit for transplant. It even has a 5x4.5” lug pattern and my existing wheels fit. The finished car should handle like a sports car. It will have disc brakes front and back.

I already have all the pieces and have been working on rebuilding everything. I am good at mechanical work and fabrication, but body work is my weak point. I get too caught up trying for perfection and get discouraged. For that reason the ‘65 project has stalled and I’m focused on the ‘63.

[TRADERMIKE 2012]

Originally Posted by tekuhn

I love the looks of the car, and the engine runs very well, but it’s just too underpowered. The clutch is garbage and the driveshaft needs bearings. It needs to be fun to drive, so V8 it will be. Also the suspension needs to be modernized. I’m building a Mustang II crossmember and front suspension with coil-overs and power rack and pinion. The rear suspension will be a complete subframe from a Nissan 300ZX Twin Turbo. The diff is perfect with 3.69 gears and over a 9” ring gear with viscous limited slip. It’s very stout and looks to be an excellent fit for transplant. It even has a 5x4.5” lug pattern and my existing wheels fit. The finished car should handle like a sports car. It will have disc brakes front and back.

I already have all the pieces and have been working on rebuilding everything. I am good at mechanical work and fabrication, but body work is my weak point. I get too caught up trying for perfection and get discouraged. For that reason, the ‘65 project has stalled and I’m focused on the ‘63.

Mikes ANSWER: I FLIPPED OVER MY MOTHERS 1975 Mustang 2. It HAD THE 302 IN IT AND I WAS ONLY USED TO driving THE Pinto. I WAS A SENIOR AND HAD RECENTLY GRADUATED. I AM LUCKY TO BE HERE AFTER THAT ONE. sounds LIKE A PLAN AND LIKE YOU SAID YOU HAVE THE PARTS.

I LIKE POWER MY SELF, NOTHING LIKE THE LARGE journal Pontiac. I LOVE THE POWER OF MY 428 CI Pontiac AND IT IS THE FIRST Big Block I EVER OWNED, EVEN IF ONE DOES NOT CALL A Pontiac a Big Block. There GOES THE CAP LOCKS SORRY.

On my 1979 Pontiac Firebird is Hurb Adams Suspension and Posi-Traction Rear plus 4 Wheel Disc. Brakes, so I agree with better Handling and Power to spare.

Adding all the NOS Options that my Vehicle is missing is my other Goal. I have a Roll Bar in the Cab and custom-made sub-frame connectors. Roll Bar in the Trunk and around the Engine too.

This Build of mine is Firebird TA from 1967 - 1981 and "not" a Retro-Mod! Installing a 1967 Pontiac 428 ci with Tri-Power in a 1979 Pontiac is more correct than the Factory Installing the Olds 403 ci ever was!

The Gear Vendors Over Drive behind the TH 400 Trans. with a B+M shifter and shift kit allows for a much-needed High way Gear to lower the RPM's with my 3.23 Rear End.

[tekuhn]

A bit more information on my SR block. Each cylinder is stamped with an S, P, or U. I assume it was to let the person fitting the pistons know something about the bore size. Standard, Undersize, P??. Also the deck machining is pretty coarse. All the machine marks are oriented in the same direction as expected, but then there are lines made by a hand grinder that are in a different direction. The hand grinding is not very well done and feel low if you rub your fingers across them. I assume that a standard thickness and composition head gasket will still seal though. No wonder they put Bars Leak in them from the factory.

[TRADERMIKE 2012]

Originally Posted by tekuhn

A bit more information on my SR block. Each cylinder is stamped with an S, P, or U. I assume it was to let the person fitting the pistons know something about the bore size. Standard, Undersize, P??. Also the deck machining is pretty coarse. All the machine marks are oriented in the same direction as expected, but then there are lines made by a hand grinder that are in a different direction. The hand grinding is not very well done and feel low if you rub your fingers across them. I assume that a standard thickness and composition head gasket will still seal though. No wonder they put Bars Leak in them from the factory.

MIKES ANSWER:
I would Shave the top of the Block to Deck the grooves out before you rebuild that Block. From what I read the Factory had to match certain Pistons to Bore size quick and to do those 3 pistons that fits all, in your case. "S","P","U", assuming they only had to mark the Bores that were different from normal for that particular Engine the letters may depict the Rings size. Next step is to lap the rings without lapping them on the assembly line so they take out the lap clearances by using different letter correspondence per Ring Clearence.

Same Bore size, same Piston size and 3 different lapped Rings to fit all the Pistons. Someone would have to measure the diameter in 3 places to find which letter Ring corresponds to that cylinder first. Then stamp that cylinder. Normal Piston with Ring won't be stamped. I watched Modern Rings being installed on today's production rebuilds to share this info. and assuming that is the way it was done in the past.

They do have a special Ring insertion tool also to make the job quicker. I think the rings are about 30 degrees away from each other. Thus, never lining up there grooves as not to lose compression.

[steve25]

If you where to use that block I would deck it again to get that the be area as it should be!
The brass, Copper and Aluminum pellets the factory put the cooling system was for just that, coolant leaks, not compression leaks!

That area on the deck of your block is right where the fire ring needs to seal!

Grooves like that of .003" in the block deck or head surface will eat up just about all the 95 ft lbs of gasket crush that's needed!

[Rocky Rotella]

tekuhn, you're right. The stamped codes in the deck surface are indicators for minute differences in bore diameter. Each letter was for a specific range and the pistons were matched accordingly during assembly.

[Skip Fix]

Which is how the term "fitted block" came about.

One of my 409 buddies with all kinds of exotic factory parts(and a complete Mystery Motor, 65 factory Hemi SS car) has the factory blueprints that are the size of a conference table that have the specs for the 409 pistons and codes on it.

[SD455DJ]

Originally Posted by Rocky Rotella

tekuhn, you're right. The stamped codes in the deck surface are indicators for minute differences in bore diameter. Each letter was for a specific range and the pistons were matched accordingly during assembly.

Here's Dan's 428HO std. bore block on tear down (never apart before) with B, C, D, and E stamps for fitted pistons to each bore. This block had 1-B, 3-C's, 3-D's, and 1-E...4 different sizes.

Dennis

[TRADERMIKE 2012]

Originally Posted by SD455DJ

Here's Dan's 428HO std. bore block on tear down (never apart before) with B, C, D, and E stamps for fitted pistons to each bore. This block had 1-B, 3-C's, 3-D's, and 1-E...4 different sizes. Dennis

Mike: Would like to see a Photo of the 1967 428 CI HO Piston Top. I have the Pontiac 1967 "D" Port Heads on the HO YK Code 428 ci Block. That is if you can and have access to that Block and it is 1967. I have never seen the 10.75 CR Piston and I have read there was a Lower CR Piston version used on the Big Body Vehicles. Since I have never had my Heads off the Motor, I am curious to see the difference between them. I have seen photos in Books but I can't distinguish between Low and High compression Pistons. All that I read is that the Low CR is Dished to Lower the CR. So, if you can provide the Two Photos showing both Low and High CR Pistons for 1967 428 CI HO Piston's, would be beneficial to my current research, thanks. Mike out.

[steve25]

I have had both the 360 hp 2 bolt main 428 and the 376 hp 4 bolt main motors and the pistons where the same dish type.

[TRADERMIKE 2012]

Originally Posted by Skip Fix

Which is how the term "fitted block" came about.

One of my 409 buddies with all kinds of exotic factory parts (and a complete Mystery Motor, 65 factory Hemi SS car) has the factory blueprints that are the size of a conference table that have the specs for the 409 pistons and codes on it.

Mikes reply: Bé nice to see the "specs for the 409"
could tell us what the letters mean as long as they were consistent across all GM Divisions.