What is differance in Ram Air III block and a Ram Air IV block ?Heres why:I brought my engine to my machine shop guy for him to 'check it out'. He was on vaction but one of his guys were there. The guy looked at the block and tried to tell me that it wasn't a Ram Air III motor. He said because of the 4bolt mains and all the extra webbing casted in the block. He also said that back in the day Pontiac took stuff of the shelf and stuffed in the cars on the production lines as they ran out of the 'corret parts'. He also said that sometimes the line men would do stuff like that when the knew a car was a special build for someone. THe block is stamped WS and the vin is correct on the block. I must assume that the stampings on the block are correct. I bought the car from a barn in 91. It had sat in since 79 when it was then last driven. The heads were replaced in 78 with 16'. According to a repair order that I had found in the glove box because they were cracked. It also had gotten a new set of headers to replace the manifolds as per the papers. When I bought the car the lady told me she hated the leaking exhaust they had put on the car when she had the heads replaced. She told me she wished she spent the extra money for the right parts and not had the trouble she got with the new stuff. SHe said since she stopped liking to drive the noisey car the time it would have took to find the right parts would have been worth it and then she wouldn't have had to put new exhaust manifolds on (headers). SO with all that rambling could anyone give me some insight on the differance between the ram air III and the Ram Air IV block???
I assume by your username, that we are dealing with a 1970 model, if so the WS indicates that yes you have a 1970 RAIII motor (manual trans) and the original heads would have been #12's. Your #16's could be large or small valve heads, if they were 69 RAIII heads they would be large valve. If so performance will be fine, just not correct #'s matching. I don't know if that is important to you or not. The 4-bolt mains aren't odd, RAIII blocks came with either 2 or 4 bolt mains, no rhyme or reason to it. The RA4 got forged pistons, while the 3 got standard cast ones. Otherwise the difference is all in the cam, heads and intake/exhaust manifolds.
A little help... 'cause we don't all have to learn the hard way!
Thanks for the info. and, Yes it a 70 model TA. The helper at the machine shop was no help in this matter.