I am currently in the process of swapping out the stock 307 in my Delta with a recently acquired 455. The block is in the shop being machined .080 over and i am thinking of stroking it out 4.500. I am open to any suggestions at all on the stroke, carb, intake, ect. I am specifically wondering what CAM i should use. I was thinking of using a 268H but again I'm not sure. My experience is limited but my dad suggested an 850 carb, either Edelbrock or Holly, and the aforementioned CAM. Any suggestions would be helpful.


P.S. I know I'll need the big block mounts and possibly the wiring harness but after that i have no clue.

P.P.S. I also have a TH350 BOP that needs rebuilding but i will be installing once complete. "Das Boat" currently has a 200R4 I do believe but again not 100% sure of that.

 

I'm guessing that this will not be your main car so how long can it be off the road and how much are you willing to put into it?

As far as the mounts go there are no "big block mounts" except in 68-71 A bodies (F85, Cutlass, 442). There is no need to change out your engine mounts, just get new rubbers from the parts store for your 307 and run it. I ran a 455 in a 1980 Cutlass on 260 mounts with no issues as the bottom of all modern Olds blocks have the same dimensions.
As far as the trans goes (this is why I asked how much you are willing to spend) I would put the money into the 200-4R. Don't get me wrong here, it's gonna cost around $2000, but it will be money well spent especially if you put some gears in it.

 

I thought that maybe the mounts would be different because they are for chevy but im not sure of the specifics as to why. as for time off the street i dont really care as right now i try to avoid driving it too much around town cause my other car gets better mileage. and as for cost its gonna be a slow build process anyways so a few extra weeks of saving wont hurt. I'm curious as to what the 200-R4 has over the hydromatic, I was told to go with it by a few different people but nobody really told me why.

Also the 455 came out of a '76 LeMans. Same bolt pattern but different car (Obviously)

 

Is is a Pontiac 455? That will change the ballgame considerably. In that case you will need to change the fame pads, but you're going to have a tough time because I don't know about the bottom end on a 301 vs a 455. For that you're going to have to ask on some Poncho boards for a good answer.

The 200-4R is an overdrive transmission and will give you much better driveability when out on the road than the 3 speed transmissions will and has a steeper 1st gear for a better launch so it's a win/win.