After giving this more thought, probably not every change a person makes to his combination will be the same. what I said earlier was my gain with the change, other heads being changed to the 305cc may make more or less HP, changing other items on a vehicle can make big gains as well, without even changing the horse power level, I put the car on a diet for example, took off 200 lbs,car picked up about a 1/4 second, changed the front disc brakes to aerospace duel piston and lighter rotors, this gained me 1/4 second, lighter wheels, driveshaft, tires, transmission, headers, exhaust, etc...will all make big differences in performance, I did several of these over the winter and picked up a second off my time without even touching the engine. Do a slide rule 1/4 mile - hp test before you change any of these items, and you`ll see, your engine will get credit for more horse power, and it hasn`t changed a thing...( other than the weight difference),It doesn`t seem right but you could start out with a 500 hp car at the beginning and end up with something that shows 600 when your done, but I still think you need more than 10 horse to gain a tenth, once you hit the 10.0 range for 1/4 mile or 6.0 range for 1/8 th ,it takes more

superstreeter I get your drift and that is some good stuff but I am a bit confussed about the 10hp to knock off a tenth/sec.

At that et range, and power level, it takes a lot of power increase, to go even a little faster. On a similiar deal, except it was a 496, that made 752hp with 049 oval ports, they were VERY re-worked, and not a typical port job, but, the rest of the engine was very basic, after running 1 season with the oval ports, in the 9.30-40 range, depending on air, with a best of a 9.298 et, at 143-145, again, depending on air, for the next season, I did nothing else, except change to a set of mildy ported Canfield 310's, same intake, except ported to a rectangle port, which was a Victor-O 4500, same cam, same everything, only change was the heads, the car ultimately ran 8.989 at 150, with a string of 9.0's. I didn't dyno the engine after the head swap. But, I did dyno it later, and it made about 70 more hp than the ovals.

I would expect, if you got the right head, and I would suggest the new revised Pro-1's, either the 325's, or, the 345's. At 3000lbs, I think the 345's would be a better choice, as, they offer a bunch of easier future potential. A 325 head, can be made to basicaly make just as much power as a 345, but, it takes a bunch more work. THe meat is there, it just has to be removed.

I would also get a new cam. THat is a very conervative cam for a 540. With a cam, and head swap, I could see it making an aditional 100hp.

Frank
Advanced Performance
www.get-ap.com

OK..so if I go with a head in the 335- 345 cc range...what kind of camshaft specs should I be looking at for this combo? Keep in mind I want to keep the thing under 7000 rpm because I am poor and can't build a new motor overnight..lol. :lol:

I wouldn;t get to carried away on the cam, but something in the low 280 at .050 on the intake, and upper 280 to low 290 on the exhaust, with .775 intake lift, and .714-.720 on the ex. I personaly would run a 112 lobe sep. With the tighter lobe sep, it should equal the mid range tq of the old cam, but, it will make more hp up top.

Have you considered just re-working the heads you already have? You said they are un-ported correct? If thats the case, for A LOT less than new heads, you could pick up a bunch of power that way. A cam change, maybe an intake change, to a super Victor, or the smaller profiler, I wouldn;t use the big profiler for 7000rpm, but, a Super Victor, with some minor plenumn work, a port job, maybe bigger intake valves, and a cam, and you would go high 5's. And, the cool part, you could say, they are just some old 074 aluminumn heads, when your beating guys with Dart, Brodix, etc. You couldn;t imagine, how mad guys got, from my above example, with the 049 oval ports, how mad guys would get, when they got trailered by old junk truck heads, when they were running their cnc'd this or thats.

Frank
Advanced Performance
www.get-ap.com

I think either of these two cams would work well for you if you are going to keep the rpm at 7000 and below:

Comp Cams 11-734-9

Operating Range: 4500-7300 RPM
Duration Advertised: 313° Intake / 322° Exhaust
Duration @ .050'' Lift: 278° Intake / 286° Exhaust
Valve Lift w/1.7 Rockers: .748'' Intake / .714'' Exhaust
Valve Setting: .028'' Intake / .030'' Exhaust
Lobe Separation Angle: 110°

Comp Cams 11-740-9

Operating Range: 5000-7500 RPM
Duration Advertised: 321° Intake / 336° Exhaust
Duration @ .050'' Lift: 286° Intake / 298° Exhaust
Valve Lift w/1.7 Rockers: .748'' Intake / .748'' Exhaust
Valve Setting: .028'' Intake / .030'' Exhaust
Lobe Separation Angle: 112°


George

Thanks for taking the time to post that..I appreciate it. That first one looks like the one comp recomended..but not for sure.

after running 1 season with the oval ports, in the 9.30-40 range, depending on air, with a best of a 9.298 et, at 143-145, again, depending on air, for the next season, I did nothing else, except change to a set of mildy ported Canfield 310's, same intake, except ported to a rectangle port, which was a Victor-O 4500, same cam, same everything, only change was the heads, the car ultimately ran 8.989 at 150, with a string of 9.0's. I didn't dyno the engine after the head swap. But, I did dyno it later, and it made about 70 more hp than the ovals.



"Thats about what I would figure..you picked up 3 1/2 - 10ths, and it took 70 hp,, thats 20 hp per 10th"

but you contradicted yourself..in your post to me you said I needed 130 more hp to get into the 5's ( gain of 3 tenths)...then you said 20 hp per tenth.not complaining,just pointing it out :wink: although you did say in the quarter..not the eighth.

I missed this post before...but I don't think the heads are worth it really...They are 1970 castings I think..yes they are stock port wise..but they have been flat milled. They are due for new valves because they have been ground several times. etc.. I had problems with the intake not fitting,had to hog out the holes..the valve cover rail on one has been broken and then welded(doesn't hurt anything,but still...looks bad and makes it harder to get rid of em if I wanted to). The one good thing is the stud bosses have never been repaired...most I have seen usually have been welded on.I just can't see spending much money on a 37 year old set of heads. I have had these things for years and am tired of fooling with them.