[stu]

How much of the accessory brackets can be reused on this swap? Thinking about it as i have a clean 403 but don't want to fool with fabbing or finding new PS, AC, and alternator mounts. BTW the 403 is the same year (79).

[stu]

How much of the accessory brackets can be reused on this swap? Thinking about it as i have a clean 403 but don't want to fool with fabbing or finding new PS, AC, and alternator mounts. BTW the 403 is the same year (79).

['ol Pinion head]

Sorry, all accessory brackets will have to be swapped to go from 301 to 403. Easier to go Pure Pontiac...400 or 455.

[larry davis]

OPH is right, nothing will swap. I don't believe the motor mounts will work either.

Why not go w/ a 400????

[Gooatee]

Well atleast you would be swaping a TURD for a TURD!LOL You would have a much easier time puting a real Pontiac motor in it as stated above!

[stu]

Are the 403's that bad? What is it that you don't like? I know the main webs are not up to 400+ HP but I can't see why it couldn't be the basis for a mild street engine. The stock heads seem OK, and I have a set of 455 Olds Ga heads that were used on the 72 W-30 which will bolt on. Also, I don't have a 400 or 455 and they are hard to find in this area. I hear a lot of talk about "weak blocks" and on and on but I haven't had a single lower end issue on anything I ever assembled including the 301 that I flog on.

[BAB]

Stu,

Your 403 will do fine for that kind of power. It is not the motor of choice..however as long as you do not exceed 5000 RPM I would run your combo. Your engine could take on 5500 however the stock oil system is in question before the strength of the motor would be since OLD's use a quart less oil than pontiac. If you want some really good advice on OLD's go to Dick Miller or Joe Mondelloe's websites. These guys have some excellent cams and good tecnical information. Mondello sells a parts book and technical guide that are super but if you talk to him you will end up doing more to the motor than you want. When he does something he likes to give advice on doing it ALL right or don't do it at all. In other words what you "want" he will tell you ..you "need"! He is a very good resouce though.

[matt66gto]

Not really anything wrong with a 403. Remember you are posting on a pontiac website therefore these are pontiac people. It is true however that I personally would try to find a 400. They can still be had at a reasonable price and will perform better with less modification. A 403 can easily make 1hp/in.

[matt66gto]

Oh yea, If you decide you want a 400 and don't mind a drive to SC I will locate one for you. E-mail me and let me know.

[stu]

I would go for a 455 if I did this. Can you find one for a reasonable price? Would need a complete rebuildable engine. I suspect they are not easy to find and not cheap when you do.

[Maurice Hood]

Stu, Pontiac 400 and even 455 engines aren’t that hard to find in NC. Especially the 400s are in most every junkyard. I helped my son get a 455 out of a 1971 big car back last winter. The yard was in Fayetteville and they had, that we saw, a number of 400s, one 428 and one 455. Go with a Pontiac engine you’ll be glad you did. .... .. Maurice

[stu]

How much was your 455?

[Maurice Hood]

Stu, the 455 we bought was guaranteed to be a rebuildable core and we paid $300.00 for it. This was back about February of this year and as I said we saw one other 455. Good luck. .... Maurice

[matt66gto]

Good reply Maurice. 455's are getting a little harder to find here, but can still be had. 400's are easy though and cheap. I assume NC is the same or better than SC. If you keep an eye on the pick and pull sometimes you can get a great deal. Especially if you get to know the people.