1963 Pontiac Bonneville Conv. Question

[DaveAspi]

Just purchased, and about to dive into the restore on this. I was told that I have a 421 engine. How can I tell for sure?

[61-63]

You need a copy of Pete McCarthy's book "Pontiac Musclecar Performance 1955-1979" where there there are pictures showing what I am describing below.

A '63 421 block has the casting number 544988. The casting number is on the rear of the distributor pad just behind the distributor. If your engine is in the car you will need one of the little mirrors to be able to see the casting number. '63 389 engines had a 543680 casting number.

The 421 will also have what is called a transfer lug just in front of the top passenger side bolt which holds the bell housing to the block. You can feel the transfer lug with your hand; it is in front of that top passenger side bell housing bolt about three inches over from the distributor. A 389 in that area willl be flat.

And finally a '63 421 would have one of the following engine codes stamped into the front of the block just under the the passenger side head; 22b, 34j, 43n, 08b, 25g, 47q, 11b, 28g, 50q, 12-5, 12u, 125t, 13-5, 13u, 135u, 24u.

The above should hold true but assembly plants didn't always follow the book, and people have been known to restamp the engine code on the front of blocks, so the only way to know for sure would be to pull the pan and measure the size of the main journals
and the stroke.

[helfen]

Swapping the the stock steering box for a Lee 12 to 1 and swapping the front upper control arms for 61-62 Pontiac B body units with solid bushings will make it handle much better...

I used a direct bolt in mid 70's 9-C-1 Police Nova variabale/ quick ratio high effort P/S box 2 1/4 turns lock to lock in my 62 Catalina. The splines on the box are indexed so that you can use the box for a front steer or rear steer car. Best of all it was a junk yard find for $10.00 bucks. You just need to know what your looking for. T/A and Z/28's of that era (1975-79) are good. Later early/ mid 80's G body Monte Carlo's, GP's are good units too, however you will need to change the hose connections to the pump from metric to SAE threads. My stock P/S box looks just the same as the Police Nova so when you lift the hood no one will know the difference.

Don

[helfen]

You need a copy of Pete McCarthy's book "Pontiac Musclecar Performance 1955-1979" where there there are pictures showing what I am describing below.

A '63 421 block has the casting number 544988. The casting number is on the rear of the distributor pad just behind the distributor. If your engine is in the car you will need one of the little mirrors to be able to see the casting number. '63 389 engines had a 543680 casting number.

The 421 will also have what is called a transfer lug just in front of the top passenger side bolt which holds the bell housing to the block. You can feel the transfer lug with your hand; it is in front of that top passenger side bell housing bolt about three inches over from the distributor. A 389 in that area willl be flat.

And finally a '63 421 would have one of the following engine codes stamped into the front of the block just under the the passenger side head; 22b, 34j, 43n, 08b, 25g, 47q, 11b, 28g, 50q, 12-5, 12u, 125t, 13-5, 13u, 135u, 24u.

The above should hold true but assembly plants didn't always follow the book, and people have been known to restamp the engine code on the front of blocks, so the only way to know for sure would be to pull the pan and measure the size of the main journals
and the stroke.

Just remember that that transfer plug (most people call it the mountain is not limited to a 421. All 195.5, 326, 350, 428, 455's have them too.
A 63 421 would have a bellhousing mounted starter. If a block has a square machined surface at deck surface on the front passenger side the block is a 421.

Don

[61-63]

I failed to mention that the car's vin will also be stamped on the front passenger side of the block just below the head if the block is original to the car. If you find your car's vin and one of the codes I mentioned above on the front of the block, and the transfer lug (mountain) I think you could consider it very likely that your car has a 421 in it.

[poci1957]

Hello Dave, congratulations on finding a great car, one of the sharpest big cars ever! I concur with everything 61-63 said, look for the transfer lug, codes and castings that he said.

I would not worry too much about modifying the front suspension or steering unless you really want to. My 1963 has all standard components but with radial tires and still feels pretty good up there. You might also take a look at PontiacRegistry.com The World's largest Pontiac Resource for another info source, but you can post questions here too. Good luck, Todd C

[helfen]

Hello Dave, congratulations on finding a great car, one of the sharpest big cars ever! I concur with everything 61-63 said, look for the transfer lug, codes and castings that he said.

I would not worry too much about modifying the front suspension or steering unless you really want to. My 1963 has all standard components but with radial tires and still feels pretty good up there. You might also take a look at PontiacRegistry.com The World's largest Pontiac Resource for another info source, but you can post questions here too. Good luck, Todd C

Hope I didn't get in your bad books Todd.

Don

[poci1957]

Hope I didn't get in your bad books Todd.

Don

Bad books? Oh no, knowing how people love to modify I just did not want to encourage him unless it was necessary.

[helfen]

Bad books? Oh no, knowing how people love to modify I just did not want to encourage him unless it was necessary.

I feel better now Todd. The reason I changed my 62's was because of a bad experience I had with the box that was in my 59's. That box is the same as the 62's.
But it looks stock!

Don

[c.johnson]

Ok, dumb but related question,

Is this also true for finding if a '64 Pontiac Catalina (2door) engine is a 421?

A neighbor wants me to help him sell a 2 door & it would be a good idea to know what the size of the engine...if I can get the hood open. Any pointers there would be appreciated also.

thanks,

[61-63]

The '64 421 block casting number was 9773157 and the codes on the front of the block would have been one of the following - 35b, 38s, 43n, 44b, 47s, 49n, 45b, 46g, or 50q.

In '64 the block did not have the car's vin stamped onto the front of the block.

The '64 421 would have the transfer lug or mountain as they call it.

The block, unlike in '63, would have provision for a block mounted starter but that isn't unique to the cubic inches of the block.

[helfen]

The '64 421 block casting number was 9773157 and the codes on the front of the block would have been one of the following - 35b, 38s, 43n, 44b, 47s, 49n, 45b, 46g, or 50q.

In '64 the block did not have the car's vin stamped onto the front of the block.

The '64 421 would have the transfer lug or mountain as they call it.

The block, unlike in '63, would have provision for a block mounted starter but that isn't unique to the cubic inches of the block.

1964 was another change over year where block and bellhousing starters were used. That year (64) the "A" body had block mounted starters and the "B" body used bellhousing starters with block mounting bolt holes. This one thing made possible Royal Pontiac's prepping the two Pontiac GTO's for Car & Driver Magazine's road test going up against a Ferrari GTO. The GTO's were ringers with 421's in them. The Pontiac- 0-60 in 4.6 , 0-100 in 11.8 and quarter mile of 13.1 @ 113mph
At that time most people didn't know about the mountain for a quick glance to see if a 421 was in there instead of a 389.

Don

[c.johnson]

Makes sense.

thanks,