[4dblnkldude]

Eventually I was going to rebuild the 400 in my 81 TA. But a deal came and I bought a 73 400 freshly rebuilt with .030 forged TRW's and an unknown cam. The cam itself has .305 lobe lift which seems pretty decent but unknown duration... I guess I can slap it back in and degree it. Anyway I'm gonna build it because I have everything I need except head gaskets and put it in with just a little more power. So we have basically a stock bottom end, 6X4 heads that looks like they were milled a little, 1.5 roller tips, a stock 71 intake, and a 7274 77 quadrajet. I will probably roll with manifolds. So the car has 3.08:1 gears and a turbo 350 transmission. I know there has to be a ton of these combos out there. So what is a nice cam for this combo? Looking for 325 or so HP... nothing crazy, just something that can fry the tires a bit and good throttle response. I do also have a new ram air iv crane muscle car cam if thats better.

[John Milner]

If it were mine, I would probably do something like a Summit 2801 cam (214/224 .442 .465 112). I would bet that the compression is around 8.5:1 unless it has been decked and the heads milled quite a bit. I would be careful to not over cam it. The ram air iv cam wouldn’t work well with that particular combination.

[25stevem]

You mention nothing about what limit your spring set up is on those 6X heads have , it would be nice to know this to assist in a cam pick?

In terms of the short block rebuild I would hope that you have a 60 psi oil pump tucked in there along with a HD drive shaft and a baffled pan that would have come on the 74 and up TA cars due to there
handling .

That 2801 cam is right there at the limit exh lift wise of what the stock 6X spring installed height can deal with, especially if your still running stock retainers and the valve guide tops have not been cut for positive Viton type seals.

[66sprint6]

I am waiting on a 2800 cam from Summit. I was going to get the 2801, as I know it is popular, but they mention changing out the springs and having a minimum 9:1 compression ratio. It's on back order, but it was less than 100.00, so I can wait.
Pretty tame at 204/214, 112 LS, but I need tons of vacuum for PB, A/C, and cruise. I also want to drive the car to work and back every day through the city, so the smooth idle and tractability is important to me.

[4dblnkldude]

Very good. It looks like stock springs on the heads. They were re done in the 80's and I got them from a friend was going to scrap them years ago. The pushrod holes have been elongated and they had factory stamped 1.65 rockers on them with polylocks. But no guide plates?? You can still see lapping compound around some of the valves. I'm not opposed to putting different springs on them. I did degree the cam tonight and it has .465 lift intake and exhaust, I did not get to any other specs yet. Maybe somebody picked this cam out close? Is that lift too much?

[25stevem]

Well lets wait until you get those heads in your hands , but in general even if they where rebuilt with brand new factory valve springs if your going to be running .465” lift they are not going to last long in the least!

From what I have seen over the years is that for good life out of the stock springs you should observe a limit of .450” lift.

If you want to run them as is with that .465” lift then plan on having a need to change them out in about 5K miles depending on how often you buzz out the motor.

[4dblnkldude]

I have the heads in my hands. I have had them for 16 years. I measured everything when I got home and it looks to me that this is a comp 218/224 462.470 lift on a 110. So I thing will work according to this feedback. Should I rob a set of guide plates off another set of heads? Steve if its not gonna last what valve springs should I use. I have a set of edelbrock 5845 brand new??

[b-man]

You must run guide plates, not optional. Apparently someone didn’t put them back on, 6X heads all came with them.

Earlier design heads (some ‘67 and all ‘66 and earlier except SD)’that came from the factory without guide plates had precision slots milled into the head castings to guide the pushrods.

[4dblnkldude]

Any harm in re-using stock head bolts? I've done it before but does anyone make new Pontiac head bolts? Thank you for the replies.

[b-man]

The factory head bolts are high quality fasteners that in most cases have seen only one torquing cycle.

I’ve reused quite a few sets with zero issues, as with any used fasteners check the threads to see if they’re in good condition and free of corrosion and pitting.