I am planning to rebuild my 350. I have a set of 601 heads, a comp 280 magnum cam, small dished pistons, maybe 9.5:1 compression, TH 350 trans a 12bolt posi with 3.31's to use. Is this a reasonable combo? Would I need a stall convertor? If so what rpm?

Gee, no thoughts? Guess I am way off base.

Are you sure those are 601 and not 681 heads? I ask because if it is in fact a set of 601 heads, the only 601 heads I know of are 267/305 heads(I think 80-86 or 87) and they either have 1.72 or 1.84 intake valves and 1.5 exhaust valves. The combustion chamber is supposed to be 53cc. that means that it would take a rather large dish to keep compression under 10:1. Assuming that your heads check out to be 58cc, and quench distance is at .040, Id take an 18cc dish in a 355 chevy to make roughly 9.5-9.6:1 compression. It will be about half a point higher if they really are 53cc. Next, if these are 681 heads, they are 62-67 327 heads(unless there are other 681 heads that I am not aware of), probably a 64cc chamber and a 1.94 valve. It would take a 12cc dish, a 64 cc chamber and .040 quench to equal roughly 9.5:1 comp. Anyways, with either head, to really get anyting out of em they should have some bowl work and a good valve job at least to make reasonable numbers with the comp cam. Another thing, your gears are gonna be a little on the low side. Id try it out, but you would do better with a 3.73, and optimally, Id go with 4.10's. I guess you could try and run that cam with a stock converter, but for any kind of good results, a minimum of a 2500 converter would be best, and Id probably shoot for a converter that actually stalls at about a 3200 rpm if you really want it to run hard. Back to the heads, I guess it all depends on what they need, but if they need totally rebuilt(which they will if they are stock cause I would not put stock springs in those heads up agains that cam) and they need ported, you would easily spend close to as much money as you would have in aftermarket heads. And with an aftermarket head, you wont be working with old technology. If they do end up being a 1.72 valve 305 head, it will be real hard to get any kind of horspower out of em over 4500 witout some extensive work. Finally, just swapping the cam to a more modest grind might sound good, but, again, its gonna be hard to keep static comp down with the 53cc heads on a 350 and a small cam and numbers approaching 10:1 compression arent your best bet. Id do some checking to be sure on those heads, and price a rebuild and port job VS out of the box aftermarket heads.

Yes they are 601 heads apparently from a HO 305. Well maybe I should consider Vortecs again or keep the heads and go with a small cam like an energizer 272?

The HO heads should have the larger of the two valve sizes(1.84). I though they had 58cc chambers, but the books say 53? Anyways, reguardless of whether its 53 or 58, here is what you are looking at. Assume they are 58cc like I think they should be. Also assume you use a standard .039 gasket and your deck surface is also stock at .025 with big 12cc dish pistons. That puts your quench at a not so nice .064, yet static comp is still roughly 9.75. With the very excessive quench, the iron heads, the high static compression numbers, and the relatively small camshaft, you have a recipe for possible detonation, especially if its a heavy car driven around town and what not. Thats why I was saying that this is tough to pull off with those heads. Here is a way you can make it work. Assuming they are 58cc, you could go with an 18cc dish piston, keep those heads of yours, have the deck surface cut to a .010 deck and use a .039 compressed gasket. That puts quench at a more liveable .049(still not wonderful but better than .064 and that will help performance and detonation resistance). Depending on the gasket bore, youd end up with about 9.4:1 compression give or take a tad. This will work well with the energizer camshaft, and the combo would be much better suited to your 3.31 gears. Plus, that cam does fine with a stock converter. About a 2200 will wake it up, but not a necessity. Double check and verify whether they are 53 or 58cc cause it will throw a monkey wrench in these numbers. If everything else was the same, but they are a 53cc chamber, that would put you at 9.9:1 compression. That will once again be tough with the energizer cam under any iron head without really working the tuneup.

If you can manage the vortec head, go for it. You will be miles ahead of the game. You could use the energizer cam, a 12cc piston and the same gaket/deck combo and still end up with 9.4:1 compression, but you will be working with a MUCH better cylinder head, and once again, the energizer cam combo under the vortec heads wont require a gear or converter change like the 280 would. You can run the 280 under the vortecs and get much better results as far as overall performance and horsepower, but once again, to get those results the heads will need better valvetrain hardware, the gearing and converter changes should be considered. Id also push the static comp to roughly 10:1(flat top pistons with 4 valve releifs totaling 6.5cc and no other changes will get you 10:1 and you can go lower than that due to the good chamber design of the vortec heads(9.5:1 would work as well).


The energizer cam and vortec heads gets my vote if this is a regularly driven vehicle cause Ive driven that cam many of times and it makes great streetable power from just off idle to about 5500rpm(probably peaks at 5100or so, but itll go to 5500 or a tad more). The 280 cam is a little more racy and it can be driven a lot, but it doesnt feel as good during regular driving. It really comes alive though when you mash the loud pedal, so I guess it just depends on what type of driving you plan to do and if you are willing to make all the changes to properly facilitate the bigger camhsaft. Good luck, and let me(us) know if youve got anything else on your mind.

Mdd; If using a full dish piston, the quench factor has little to no effect. You're best bet is the Vortec head/flat top piston combo. The Vortecs are efficient enough to work with with a loose quench of say .065", while the old style "D" chamber HO heads are not. Even with a full dish, the Vortecs will be less prone to detonation, but you could run 9.7:1 with the Vortecs and flat tops, or 9.1:1 with the full dish, on the same 91-93 octane pump gas. The flat top combo will definitely make more power!

As for the cam, I'd definitely go with a dual pattern for the street if the heads are left stock. If you bowl blend and lightly port the exhaust side, then go with the single pattern cam. I'd look at a hydraulic cam with a duration at .050" of 220 to 226 degrees, or a solid at 230 to 236 degrees, assuming a compression ratio of or near 9.7:1. Use an Edelbrock Performer RPM intake, and a Holley 600-750 cfm vacuum secondary carb, and you should pull 400+ horsies.

Hope this helps, Steve

i think 400+ horses is a little optimistic
maybe 320 but once again thats jmho
shane

I currently have a Comps XE 262 in my 350 powered 71 Chevelle. It has Vortec heads with the stock springs and 18cc pistons. It pulls nicely but I want you guessed it, more performance out of my new 72 Chevelle. It will not be a daily driver so I am looking for a combo that will yield more torque than the 71. I did not think I could get much out of the 601 heads and they are 58cc. The engine in there came with them so I wanted to see if anything performance wise could be done with them. I am now thinking Vortecs with the XE 268 or maybe the XE274 and a 2200stall convertor.

The XE 268 is also a nice street cam that does good in many driving sutiations. The 274, like the 280 magnum cam, is a little hotter, and would do best with a little more gear than what you got and a little more converter. But the 268 cam with the 2200 converter and 3.31 gear and a vortec head with somewhere in the neighborhood of 9.5:1 compression would work pretty well. Probably something like 360 horsepower(you could probably wring a little over 380 out of it with an optimum tuneup), but the torque should easily make that level and I wouldnt be surprised if it eclipsed the 400 ft lb mark.