I recently bought a nice fixer upper. It's a 67 428, with a 4-speed manual trans that runs pretty well! My question is, what's the deal with the 428s? It seems like this was an engine that some dealers put in the car, but it is not one of the original 3 engines made for 67 firebirds? And more importantly, were all the 428s ram air intake? If so, am i robbing it of power by not having ram air?

thanks for anyone who can help. I am trying to learn as much as i can about my new hobby.

Ben

Ben, welcome!

The 428's were never installed in any 67-69 Firebirds, or 67-69 GTO's. There were a few dealers that did engine swaps, but those are extremely rare. You would need extensive documentation to prove that a dealer installed a 428 into your car when it was new. The 67 Firebird was only available with the OHC-6, 326, or 400.

The 428 is a pretty stout engine. Nearly all 428's had 4-bolt main caps, something that's desirable for the Pontiac guys trying to make massive power, using a Pontiac block. In stock form, the 428's are great runners. The 428 was produced between 1967-1969, and used in Grand Prix's, Bonnevilles, and Catalinas. None of the 428 powered cars had Ram Air.

People new to Firebirds, and especially those familiar with Chevy's, seem to want to spread the COPO/Yenko idea to Firebirds

You know, the "Hey I found a 427 in my Camaro, it must be a Yenko and worth a fortune" routine.

Thanks!

So how do I find out what I am working with here? There is a 7 digit number (0610520) next to the YH engine code, will that tell me what engine I have or do i need to keep looking?

The YH engine code may be 428...or it may be 421, 400, 455, or even a 301.

You will need to find the block casting code behind the right cylinder head. It's cast into the upper webbed surface of the block and will typically be caked with oil and dirt.

In addition, there is a block casting date in the vicinity of the distributor base, along with the block casting code it will positively identify your engine.
http://www.yearone.com/updatedsinglepages/id_info/pontiacengineid/pontengid2.html

Got it thanks! I found both codes. Looks like it is a 428cc engine from 1968 based on the 9792968 code and the date code G038. Am I missing something or is that right? I am not sure since there seem to be a lot of potential redundancies and overlaps with these engine codes. Not a very well thought out plan it seems (like you said, YH could be any one of 5 different engines).

Thanks!

Ben

This:
http://www.teufert.net/pontiac/bloccast.htm

lists that block number as a 68 428 or 69 400. The July 3, 1968 date code points to the 428.

Year Engine HP Engine code Trans CR Cam Head Code BBL Carb No. Misc
1968 428 375 HP YH A 10.5 067 16 1-4 7028268 GP Block Casting # 9792968
1969 428 360 HP YH A 10.5 066 46 1-4 7029268 45 deg int. Bonneville Block Casting # 9792968

When you look at the VIN on the block face next to the timing cover, you'll see that it does not match your car. The 428 was not dealer installed (that it has a YH code, a stamped engine unit number that does not match your billing history, and the VIN will provide the trifecta) but it's a great combination. Congratulations on a nice find!

Mrytle Motors and Royal Pontiac did the 428 swap on 68 cars and they did have ram air. I have a copy of the September 1968 Popular Hot Rodding magazine with an article about this swap showing a ram air air cleaner. I have this scanned into my pc. If you would like a copy send me a pm.

The 428 in that Firebird...if indeed a Royal Pontiac, Myrtle Motors will not have a VIN stamp or a engine unit number of the same font or appearance as stock.

The 428 in that Firebird...if indeed a Royal Pontiac, Myrtle Motors will not have a VIN stamp or a engine unit number of the same font or appearance as stock.

A 428 block has "428" cast in the block on the left side between the frost plugs. Easy to see. That tells you if you have a 428 or not the rest of the numbers will tell you the date and place it was made, whether it was for and auto or manual, etc.

What heads do you have on it?

You can tell what the engine is by the date and engine or engine casting code on block...if you didn't want to get dirty.

My comment earlier that '...none of the 428 cars had Ram Air' was in reference to the factory 1967-1969 Grand Prix's, Bonnevilles, etc.

Yes, Royal Pontiac and Myrtle Motors did engine swaps, but they did not restamp engines to have the VIN match the car. Their conversions were simply that, conversions done at the dealer. The same swap could have been made in your garage back in 1968. The appeal and value of an original Royal Pontiac car is the documentation showing that someone back in the day had Royal (or another dealership) change engines under warranty.

Some of the lesser known dealers also did engine swaps to GTO's and Firebirds, many of those dealers we never heard of, because they didn't receive any media attention.

IF they were changed at the dealer when new, wouldn't they use a new "service replacement" engine? Seems to me if it was exchanged later with a block from another car it would have the vin stamp of the original car the engine was 'borrowed' from.

I believe they were SR blocks that they used. They pulled your original 400 (or whatever you may have had), and installed a 428 they ordered as a Service Replacement. They gave you a credit for your old engine.

The dealers made out quite well on these deals, because they charged you $600+ for the new engine, then they took your old engine (which typically had very few miles on it), and stored it the service area to be used a warranty replacement for another vehicle.

I recall reading somewhere that there were very few conversion cars made. Car And Driver did the write-up on a 1968 Royal Bobcat GTO with a 428 transplant. From what I understand, there were only a handful of conversion cars made due to the high cost. People opted for the Royal Bobcat package on their existing GTO or Firebird.

The articl I have states that the engines were "390 hp out of the crate" so I would agree that they were service replacement blocks. They then installed a ram air cam and heads from a ra 400, cc'd the heads, heat riser blocking gaskets, thin head gaskets and a recurved dizzy and bigger jets in the carb. The engine is rated at 450hp and 465lbs./ft at 3600 rpm. What a beast! The car in the article ran a 12.55.