To cam or not to cam

mustangdave · Dec 22, 2006

Is it worth it to put a hotter cam ina stock 302, stock heads. The only mods are RPM Air Gap intake, headers, dual exhaust. If so, what is the most you would go. Is a "268" cam too much?

danny clemens · Dec 22, 2006

You could definately use more cam. You can call Comp Cams up and they'll recommend a cam for your engine.

Some mild port work would help your heads.

D.Hearne · Dec 22, 2006

Comp's 268H is a good choice for a stock compressioned, daily driver 302. Works with the stock springs and valve train. What carb is on the AirGap ?

mustangdave · Dec 22, 2006

Holley street avenger 570.

D.Hearne · Dec 23, 2006

Good combo. Go with it. Won't be a top end screamer, but will be good for all around and daily driving over the stock parts.

67Dylan · Dec 23, 2006

IMO, if you're using E7 untouched heads you are going to be greatly dissapointed, unless you expect ~10 hp gain and will be happy w/that. If you want the most, mill the heads, have port work done on them, and change the cam. If you're going to spend the money changing the cam you might as well do the heads

Max Power · Dec 23, 2006

I disagree. The seat of the pants feel will me more than 10hp. I did this many times back in the days before aftermarket heads, and a decent cam always made a pretty good difference. It will not be a screamer, but you will definitely notoce a difference.

D.Hearne · Dec 23, 2006

Max Power said:
I disagree. The seat of the pants feel will me more than 10hp. I did this many times back in the days before aftermarket heads, and a decent cam always made a pretty good difference. It will not be a screamer, but you will definitely notoce a difference.

Ditto

D.Hearne · Dec 23, 2006

Opening up the exhasut side of the stock heads will always help things, but isn't necessary to acheive gains in the "seat of the pants meter" in a cam swap.

mustangdave · Dec 23, 2006

Since I would have to remove the heads to check p/v/ clearance, I could easily open and smooth the exhaust ports. It sounds like most think it would be worthwhile. It may be years before I can afford a stroked, aluminum headed monster so I am just looking for a little more fun on a no-dollar budget.
I e-mailed Comp Cams for a recommendation but haven't heard back. They will probably suggest a lesser cam from what I have heard of them (err on the side of caution to prevent unhappy customers).

67Dylan · Dec 23, 2006

Max Power said:
I disagree. The seat of the pants feel will me more than 10hp. I did this many times back in the days before aftermarket heads, and a decent cam always made a pretty good difference. It will not be a screamer, but you will definitely notoce a difference.

Stock E7 heads flow like crap, that can't be disputed since the numbers don't lie. Opening up the heads and mill'n them to achieve more CR will do more than a cam swap alone; which is the point I was making. Try as you may, but a bottle neck will always be a bottle neck until you address it; stock E7's quite flowing at .400, they DECREASE flow at .500. Port them correctly and you can get flow up to .600 easily. I agree w/youy tho, a difference will be noticed, but the butt can't determine the difference betwen 10hp and 15 hp; so how did you determine what your actual hp gain was? Ed Curtis, who grinds cams for NMRA racers, will also tell you the same thing about the E7's and aftermarket cams. I'm SURE he knows what he's talking about. My view, as Dave pointed out, if you're doing the work and spending the money for a cam swap, you might as well touch the heads since one has to come off anyway.

67Dylan · Dec 23, 2006

For your reading pleasure:

http://www.tmossporting.com/tabid/330/forumid/42/postid/1684/view/topic/Default.aspx

Feel free to peruse thru his pages as he does phenominal work. BTW, the car is local here and has run 12.9's in nearly stock trim PRIOR to the head, cam, intake swap .

jtfairlane · Dec 23, 2006

67Dylan said:
Stock E7 heads flow like crap, that can't be disputed since the numbers don't lie. Opening up the heads and mill'n them to achieve more CR will do more than a cam swap alone; which is the point I was making. Try as you may, but a bottle neck will always be a bottle neck until you address it; stock E7's quite flowing at .400, they DECREASE flow at .500. Port them correctly and you can get flow up to .600 easily. I agree w/youy tho, a difference will be noticed, but the butt can't determine the difference betwen 10hp and 15 hp; so how did you determine what your actual hp gain was? Ed Curtis, who grinds cams for NMRA racers, will also tell you the same thing about the E7's and aftermarket cams. I'm SURE he knows what he's talking about. My view, as Dave pointed out, if you're doing the work and spending the money for a cam swap, you might as well touch the heads since one has to come off anyway.

When did he say he was using E7TE heads? This is in the classic tech section, so I'm assuming by 302 he's referring to an early 302 and not a late model roller 302. Unless you happen to know that he is running E7TE heads, than all of your talk about the E7TE heads isn't specifically t relevant to him.

mustangdave · Dec 23, 2006

True, it is an early block...no E7TE's here. It is an Autozone rebuild that I never installed. Still, 67 Dylan's theory is probably correct: I imagine late 60"s early 70"s 302 heads flow about the same as E7TE's. I base that on the fact that they made about the same h.p. and torque in 1968 as they did in 1987-93. 200-225 h.p. and 300 lb. ft. of torque, give or take a little.
Being an Autozoo rebuild, I can't be sure of what heads or pistons I have unless I break the top end down. I requested a 68 but who knows what is really there.

FullRace · Dec 24, 2006

Numbers numbers numbers.... A man once said that if your results disprove your theory, believe what you see and make a new theory!

Max Power · Dec 24, 2006

Agreed that the whole system is only as good as its smallest restriction, that is a given. Stock 302 heads are about as bad as they get. ( I wasn't even thinking of E7s, FWIW) But....

The original 302 cams were so crappy, and many early to mid 70s ones were retarded at the timing chain, so a cam and gear swap can make a noticeable difference. I did this mod often in the 70s, and while dynos were rare then, it usually felt like well more than 10hp, depending on the combo.

I had a 69 coupe that I swapped a 302 into, and had a mild 4 barrel, stock cam, and headers with it. I switched to a higher rise intake, a healthy Crower cam, and a carb tune and picked up a second and a half in the quarter. That's more than 10-15hp, and that you can definitely feel in the seat of your pants. All on stock 69 302 heads.

I am a huge advocate of aftermarket heads, to the point I think people should throw away stock castings rather than service them, so don't think I am in love with stockers.

Regardless what the numbers are, even with the stock heads, its a worthwhile modification

D.Hearne · Dec 24, 2006

mustangdave said:
Since I would have to remove the heads to check p/v/ clearance, I could easily open and smooth the exhaust ports. It sounds like most think it would be worthwhile. It may be years before I can afford a stroked, aluminum headed monster so I am just looking for a little more fun on a no-dollar budget.
I e-mailed Comp Cams for a recommendation but haven't heard back. They will probably suggest a lesser cam from what I have heard of them (err on the side of caution to prevent unhappy customers).

You don't have to remove the heads to check clearances with the 268H. It's not that big a cam to have to worry about this. The Comp 268H is about the smallest "bigger" cam I'd contemplate doing a cam swap with. Anything smaller just doesn't seem worth the effort to me. I would pull the heads to open the exhaust, but that's just me. It isn't something that HAS to be done with what you're doing.

57fairlane · Dec 25, 2006

67Dylan said:
Try as you may, but a bottle neck will always be a bottle neck until you address it; stock E7's quite flowing at .400, they DECREASE flow at .500. Port them correctly and you can get flow up to .600 easily.

Just to clarify . . . stock E7s go static right around ~.480" which is probably why the B-cam is set right there.

I ported a set and they went 208/155 @ .500" at 28" of H20 with stock valves.

The guy I work for installed 1.94/1.6s for a guy that went 232/172 @ ~.540.
I would doubt that any set of E7s flow past .550"ish.

67Dylan · Dec 25, 2006

jtfairlane said:
When did he say he was using E7TE heads? This is in the classic tech section, so I'm assuming by 302 he's referring to an early 302 and not a late model roller 302. Unless you happen to know that he is running E7TE heads, than all of your talk about the E7TE heads isn't specifically t relevant to him.

That is correct, I am ASSUMING he is using E7's. Stock late model heads, as you pointed out, flow MUCH worse in lower range than E7's, which plays into my point even MORE. So I was giving him the benefit of the doubt....

mustangdave · Dec 26, 2006

The thread from the dead........ I just realized that I would probably need screw in studs on the heads to be safe. Anybody know an average machining cost for this? Also, can I still use stock rockers with them?

To cam or not to cam

My rearend needs a stud and two nuts.

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My rearend needs a stud and two nuts.

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