mp71conv

I have found a 455 #396021/F. which tell me it's a 68-72, but the heads have a J stamped on them. It is apart and the block has already been checked but that is it, and he wants $275. I don't know about the J Heads.
Are they worth using or should I go aftermarket?

Olds64

Is this person asking $275 for an entire engine that is disassembled? If so, I would jump on it like a rat on a Cheeto. If he wants $275 for the J heads alone then he is crazy.

J heads are the smogger heads for BBO engines in the 70s. They aren't the greatest heads, but if you are just building a street machine on a budget then they aren't bad either. Personally, I got a pair of C heads for my engine (it orignially had J heads on it). I wouldn't suggest the aftermarket Edelbrock heads unless you are going to race your car consistently.

joe_padavano

Don't believe everything you read in the FAQ. Be sure to check the VIN derivative stamping on the block. That will tell you exactly what year the block is. Lots of 455s had J heads installed as exchange heads during a valve job (my 69 442, for example).

Whether or not the J heads are worth using depends on what you plan to do with the motor. With a very mild port cleanup (grind the A.I.R. bumps, for example) and big valves, they would be perfectly fine on a full size cruiser. If you plan to do radical porting, they have the same potential as any BBO head (and are a lot less expensive). There's also the added "sleeper" factor (assuming the spectator even knows what a "J" head is...).

mp71conv

what will the vin derivitive tell me

joe_padavano

The second character is the year of manufacture ( 8 = 1968, 0 = 1970, 3 = 1973, etc.).

65-F85

So what does the 396021/F tell you about this motor? Is it a 69? and the Fa number here, but the F only by the oil filter mean it is a "f" or a "fa" motor I am looking at one with the same numbers

Thanks Gary

Vega

It will only tell you what the motor is, i believe that is the code for 455. Beyond that it wont tell you anything else. Look on the block in the front drivers side below the head. More specificly directly below the letter IDing the head, its at the very top and can even look like its part of the head, it will say something like 36M#### or something like that, first digit means Oldsmobile, second is year of manufacture.

Vega

This is what you will be looking for
2nd digit here is "2" which means 72. 3 4 5 or 6 would match J head

I dont believe the VIN derivitive will tell you anything, just a way to match it to the car

Allan R

Hey there Gary, wow you sure picked an old thread to revive. When I first started reading it I thought that some of our old buddies had come back from overseas. Then I looked at the date....

From 68-70 the casting was F in 'sans serif' typeset, so it would look just like the F I just typed. From then on the F was in 'serif' font so it would look like this: F If you're looking at an FA casting that was 72-76 (3rd run of generation 2 BBO) Don't get this confused with the heads, because they also have castings. Right now we're just talking about the block numbers/castings

396021 is the casting number for all 455's from the years 68-76. If you want to know the year, you have to look at the engine stamping pad like in the pic Vega posted. Great pic BTW Vega. The engine stamping pad is a little awkward to get to if you just want to read it. It's directly below the #1 spark plug on a 'downward facing' machined flange. Usually the PS bracket is in the way too.

Vega's pic shows a pristine stamping. This is usually how they are found. (this is on a 350 so the head shows a number instead of a letter, but the position of the stamp pad is the same:




The castings on the heads will further break down. For example: The large J on the heads was used on the 73/74/75 and 76 455's . Further breakdown: if you look at the castings just above and to the left side of the spark plugs you will see a set of 3 number on each side (the pattern will be the same above all 4 spark plugs) - All J heads should have the casting 411 783
All KA heads have the casting 413 191

Also, the 6 VIN derivatives should match the cars last 6, the trans stamping or plate, and number stamped onto the frame.

Helpful hint: there's a tech tab at the top of the C.O. forums page you can use to drill down info on the engines, id, general info etc. The other 'special info' about the head casting numbers is found at Wild About Cars. It's free to join and if I can find stuff there, anyone can. Like a buddy of mine in Ont would say, I encourage your Olds addiction!

65-F85

Thanks for the info. I just joined about 4 or 5 months ago. So all the post are new to me. I have a fairly nice 65 cutlass holiday (finally got pic posted), with a 330. I am torn between building the 330 or pulling and keep it unmolested. Would like to find a good hi compression 455 or 425 to rebuuild. Real F code block and c code heads. But I may do the LS swap and spend more on supesion. I like the twestie roads..

Yep I'm a newbie here
Thanks again Gary

65-F85

Where do I put my pic's to default to my profile?

Allan R

Everyone has that dream. You could keep it stock for now and play with BBO power later? Most important thing is keep it driving for now....I like them twisting roads too! Liked finding out what was just over the horizon and around the next corner.

If you're wondering about putting something under your name? Its called an 'avatar'. Go to your user CP and install it. You can also install a custom 'signature' pic and line in CP area too. There are limits on the size (jpeg) of the image you can upload though.

Vega

Thanks Allan! A little degreaser, a wire brush, and some patience go a long way xD
Actually that 72' block i have is just an F block, makes me wonder if the 68-72s were F and 73-76 were Fa. Either way its the same block though so i guess its irrelevant haha

65-F85, where are you located? 455s arent too hard to find for cheap in certain areas. A simple piston swap will get you higher compression as everything else was pretty much the same on all 455s. Head chamber volume, piston to deck height, all of it was pretty much the same (i say pretty much because theres a rumor that some W30 heads were milled for higher compression, if so theyd be rare and so expensive that itd be cheaper to just buy aftermarket anyway). but yes, a simple piston swap will get you where you need to go. C heads arent too hard to come across, keep an eye on the parts listings on this site and you should find some pretty quick, check ebay from time to time too. My advice would be to find a 455 core, any core as long as its in good shape. The heads and pistons can be swapped cheaply to make whatever you want out of it and as previously stated all 455s are the same with exception to piston CC and head code. All cranks are the same too whether theyre N or standard cast. There are forged cranks but theyre rare and unecessary, the cast cranks will take just about anything you can throw at them. Also all the 455 stuff should swap over perfectly with your 330 i do believe. Brackets, pullies, water pump. Its basically a longblock swap

J-(Chicago)

This thread is old , and incorrect. Just posting corrections here.
I have had a 1974 F block here before.

As vega pointed out, the way to tell the block year is on the driver's side front boss under the alternator bracket.