I almost hate to start this again. 302, not a DZ or MO, 30 over, speed pro L2210AF 15.4 dome, 64 cc 461 double hump heads 2.02/1.60 port match to Victor JR 650 demon and I think Crane 298h hyd cam. I want to tone it down just a bit and change the heads and cam. The heads do not have the hardened seats and I have to mix gas. The compression is specd at 12.5:1, but using the available comp ratio calculators assuming zero deck and 4.166 gasket bore it comes ot 11.85cr. I want to use an aluminum head with 180cc runners to keep velocity and probably change the intake for a lower range than the Vjr. I want to change to a comp cams retro hyd roller with a lower power range like 1800-5800 or so, There are a range of chamber sizes, most of whichwill drop the comp ratio too low for my liking. Brodix has a jj180 with 180 cc runners and 67cc chambers. Give me some legitimate thoughts. I don't need to go mach1 with what little hair I have left on fire any more but don't want a slouch. It only drives 200 300 miles a year, Thanks

Man you opened a can of worms with this thread.I will be the first to give an opinion. I say pull the 302 and build a 350 with flat tops a Edelbrock RPM intake the Brodix 180 heads and Comp cam. The 350 will have more bottom end than the 302..

That is exactly why I asked for legitimate opinions for this engines. I am well aware of torque differences with longer strokes. I built it for a reason in the mid 80s and nothing has changes much for THIS car.

If your going with a different heads cam setup, you need to change out that intake. If you want a motor that isn't going over 6,000 then you need a performer rpm dual plane intake or something similar. It will help you build more torque in the lower rpms to get you off the line. When you say retro comp hyrdraulic roller, which one are you referring to? The 280HR?

I built your motor in the comp cams camquest program.

Brodix IK 180 Heads, 70 CC Chambers, used flow #s on Brodix website.
15 CC dome pistons
4.166 head gasket bore
.039" thickness
decked block
4.030" bore
X4270HR comp cam
small tube open headers
660 cfm carb
dual plane high flow intake


548 HP @ 7,500
452 ft lbs @ 5,000

The specs on the cam are
270/274 advertised duration
220/224 duration @ .050
111 LSA
107 intake centerline
.474"/.474" lift

1500-5500 rpm.

A 302 is a high winding motor. That is what it does well. I was shocked when I saw the peak power with this small of a cam. The dynamic compression came in at about, 8.4:1 and the static compression was around 10.7:1.

Thanks for your reply. You see what i see in that it looks unusually high. You went a little further in detail on the same program. Yes, I was looking at the 280 HR and others. I actually thought the 280 HR might be too small compared to what I have, As it is now with 80s technology it will pull to 7500 easily, but I don't usually want to and in Houston there are not many oportunities to do it. I do want to bring up the low end power and response up a bit like with a performer rpm air gap for better low end signal. I was just afraid that too much head cc with the short stroke would kill the compression too much and thus the power. With the new tech I was thinking I could get a little more drivability without sacrificing too much power. The thing now sounds awesome at a lopey idle and screems when necessary. I still wonder about the programs calcs. Seems too high. Thanks again for your insight and reply.

Imho, 180 port heads;

disassemble her and machine the piston domes down to 11 to 1 CR. height IF they are solid dome, then rebalance;

And then install this cheap little $45 last time I looked PAW copy of this Elgin solid lifter cam and go!

E-1133-P; 280/246, 108/106, .498”, Lash, .030” and .030”. (PAW calls it a 264/246, 108/108, .498"/.498").....

I figure if you de-nut the little high-strung, rpm jewel, you will eventually come back and want to put your foot in her like she was made to run in the 1st place is the only reason I'm chiming in!!

And I have that cam in my bedroom closet for my next junk292/301 engine that I'm going to shift at 8,000 rpm just for the fun of it!!

pdq67

67SS&99SS, I looked again and see a typo I guess, You typed 548 and I think you meant 458 @ 7000 which is what I got. Still Higher than I thought. The torque I got was only 409 @ 4500. You may have entered a few different parameters. Still seems high for a small cam. My copy of the program will not take the 30 over bore and the compression is a little more generic. I am also seeing some different specs for the 280HR, 525lift, 224@50, LC 110, intake cl 106. Do you have a different version of camquest?

350 is a better choice all around

67SS&99SS, I looked again and see a typo I guess, You typed 548 and I think you meant 458 @ 7000 which is what I got. Still Higher than I thought. The torque I got was only 409 @ 4500. You may have entered a few different parameters. Still seems high for a small cam. My copy of the program will not take the 30 over bore and the compression is a little more generic. I am also seeing some different specs for the 280HR, 525lift, 224@50, LC 110, intake cl 106. Do you have a different version of camquest?

No, its not a typo about the hp/tq, amazingly. However, there was typo in my first post about camquest. I was using Desktop dyno 2003. The programs are so similar I guess I got them confused. I used every spec from comp cam's website, brodix's website and pat kelley's dynamic compression calculator when I entered in the numbers. I did a double take as well, and changed a bunch of specs, and then changed them all back because I thought it may have been an error in the program. I got the same results again. Its a smaller cam, but most people base cam sizes for a 350. I would say that it is a moderate cam for a 302, based on the way the hp and tq curves look. The roller lifters make it so much more efficient. I'm guessing the increased ramp rate of the roller cam is probably the largest contributor to the increased gains in hp over a flat tappet cam. I didn't spec the 280HR, I spec'ed the X4270HR comp cam. It says it in my post. The initial poster of the thread was looking into the 280 HR cam. The X4270HR seemed like the best fit cam for the motor in the dyno program anyway.

You are correct, I missed the cam spec in your list. I think the technololgy of the new cams vs 30 year old cams has come a long way. I think I'll mull it over for the weekend and just pick what I think is right. Thanks for your input.

I don't believe a 270/220 hy-roller cam regardless will produce this much power at these rpm's! Solid roller, MAYBE.............

What's it got at .200"?? 175 duration??

"548 HP @ 7,500
452 ft lbs @ 5,000

The specs on the cam are
270/274 advertised duration
220/224 duration @ .050
111 LSA
107 intake centerline
.474"/.474" lift"

Maybe right about the modern cam lobe designs but this is just too much for me to believe unless it has an LS-topend on her!

And, imho, I have yet to see a N/A'd 302 above 500hp!! I figure they are out there, but I ain't seen one is all.

Please help me out here.........

pdq67

I don't believe a 270/220 hy-roller cam regardless will produce this much power at these rpm's! Solid roller, MAYBE.............

What's it got at .200"?? 175 duration??

"548 HP @ 7,500
452 ft lbs @ 5,000

The specs on the cam are
270/274 advertised duration
220/224 duration @ .050
111 LSA
107 intake centerline
.474"/.474" lift"

Maybe right about the modern cam lobe designs but this is just too much for me to believe unless it has an LS-topend on her!

And, imho, I have yet to see a N/A'd 302 above 500hp!! I figure they are out there, but I ain't seen one is all.

Please help me out here.........

pdq67

Flow Numbers on brodix IK 180 Heads 2.02 intake/1.60 exhaust

Valve Lift/Intake/Exhaust

.200"/138/112
.300"/188/149
.400"/234/167
.500"/243/175
.600"/245/178

462 Camel Hump heads, 2.02/1.60 valves

Valve Lift/Intake/Exhaust

.200"/119/91
.300"/167/121
.400"198/134
.500"/212/139
.600"/218/142


pdq, I was told that the N/A 302 built by nelson racing engines was a 500+ hp motor, and it turned 8500 rpm. I do not know if this is an internet myth, but I doubt it is considering that it came from Tom Nelson's shop. That guy can build some race motors.

http://www.nelsonracingengines.com/videos/highrevhigh.wmv

After rechecking both programs, I did build the motor in camquest. It has been a long week.:confused: Anyway, I built the same motor in DTD 2003 a few mins ago and got the results I thought were right and they line up with your intuitions pdq.

442 hp @ 5500
420 ft lbs @ 5500