1969 pontiac 400 into a 78 Grand Prix

[buzz77]

OOPS, sorry. Its been sitting in the shop for so long i forgot the specs. So had to pull out my binder with all receipts. They are #62 heads. It was from an automatic car. The wallace lists those heads as having 330hp with a 10.75 cr.

I used low deck which kind of worries me, i hear the concaved pistons are better. Looking at the Wallace chart the heads are not original to the block. The block is a YC code used for the years of 1968-69, the casting date of my block is for February 1968. The 62 heads were coupled with a few different block castings from those years but YC wasn't one of them.

 

[buzz77]

Since this is the only place that would appreciate these pics. If you expand the thumbnail on the one pic you can faintly see the 62 casting on the head.

 

[Bonnewagon]

That motor looks great! Sorry, I've been screwing with a boat all of June which is very time consuming nonsense. So it would seem someone took a garden variety 2 barrel 400 and put some big valve 4 barrel heads and intake on. That was and is a very common procedure. Low deck pistons is one way, dished is another, but in the future remember that the low compression "smog" heads that everyone scorns were tested to flow almost as good as the famous ones. 4X and 6X, are very common and with stock pistons put the compression at around 8.5 which is perfect for today's fuel. I love seeing a classic Pontiac motor going into a Pontiac G body!

 

[buzz77]

Thanks for all your replies! Finally progress is being made and fingers crossed that the break in of the engine goes according to plan. One thing i was wondering is that im going to install the f41 steering box with o-ring power steering pressure hose. I have already outfitted the valve on the power steering pump with the correct valve out of an 88 IROC pump. The power steering pump is an original 1970 pump out of a Bonneville. All the brackets are 1969 1/2- 1970 brackets as are the pulleys, Now I have a question. Should i get the power steering hose found in the Monte SS and Olds 442 G-body or the one for an Iroc? I noticed the camaro hose was about 5 inches longer and since the Pontiac 400 engine seems to be a bit taller than the other standard engines found in the GBODY. So guys will the G-body specific hose fit onto the 400 or should i get the slightly longer camaro version? thanks

 

[UNGN]

Low deck pistons is one way, dished is another, but in the future remember that the low compression "smog" heads that everyone scorns were tested to flow almost as good as the famous ones. 4X and 6X, are very common and with stock pistons put the compression at around 8.5 which is perfect for today's fuel. I love seeing a classic Pontiac motor going into a Pontiac G body!

This seems to be the case across all of the detroit mfg's. Unless the heads were made with ridiculously small ports or paper thin castings, the ordinary, junkyard smog heads can be made to flow better at "street" valve lifts than OMG! I HAVE TO HAVE IT! holy grail performance heads.

The Smog heads have material to remove to shape the ports for optimum flow, but the performance heads may be missing too much material in that area to do anything with. Sure they flow more air at .800 lift, but who cares on a street motor?

 

[Bonnewagon]

What is more important than hose length is what kind of hard line is on the steering box end. I used the original V-6 "O" ring box, pump, and hoses. So my Pontiac V-8 ended up positioning the pump almost directly above the box so the lines were too long. That worked out because the pressure hard line bent 90° and ran six inches forward. It was easy to loop the extra hose on the way to the pump. It would be great if the box pressure line exited straight up- but they don't. If you can- eyeball some pictures of the hoses you want to use in an actual car. Pay attention to the hard lines and see if they can work for your application.

 

[deanlemans81]

I kept my v6 steering box and pressure and went with a 301 pump. The presure hose just needed a little tweaking to fit.