180, 200+cc heads???

[88bluestar]

I hear many different opinions on this and trying to see what makes the most sense with respect to cost and power. What makes the best power for a dirt track engine, cast iron heads only with 23 degree angle.

180cc runner or larger, valve size, etc?

7000 rpm max 3/8" dirt oval
3000 lbs car with 8.5-9" tread
10.0:1 compression/360 max cid
830 cfm carb Holley 4 bbl
2716 edelbrock intake with 1" open spacer. 2701 can also be used if not vortec related
stock block small block chevy
std weight forged crank, 3.50 stroke
380-400 gm piston weight
low tension metric rings
Jones race cam

[mark_follweiler]

is the 7000 mandated or something you picked? what about the cam?

[88bluestar]

Yes, 7000 is the rev limit per rule.

244-248 @.050, .352/.359 cam lift, 1.6 on intake. 108 LSA

[GARY C]

If it has to be as cast the heads are usually smaller than the advertised #, for instance the RHS head pours around 195cc.

[mark_follweiler]

as cast? porting allowed?

[sanfordandson]

The 830 carb is way to big.

I'd go bigger on the cam as well. 244/248 is good for a 2bbl but small for a 4bbl. 250/250 would be my choice.

I'd do a 180 runner. Anything bigger can be lazy on the bottom end. You'll want bottom end on a 3k lbs car.

[88bluestar]

Porting is allowed

[GARY C]

Then I would start with the 180 and a good head porter to utilize the best port for the rpm band you will be operating in.

[lefty o]

id go back in time with the heads. a well ported set of sportsman II's, and add another 10degr to both sides of the cam.

[mark_follweiler]

Then I would start with the 180 and a good head porter to utilize the best port for the rpm band you will be operating in.

this would be the way to go.

[Carnut1]

I am guessing 355 ci? Ported 180cc heads will deliver if done right they will finish about 205cc.

[88bluestar]

valve size? any advantage to a larger valve

[Carnut1]

If you are running a 4.03" bore I would not go larger than 2.055" intake.

[user-29956]

52.8mm valve on that bore size should be considered maximal!!!!!!

[dirtracr5]

Im my experience the 180 head would be perfect. We build a spec 360 10.5 to 1 engine on gas with a 4bbl and make about 450hp 460tq. We turn 7400 rpm in a 3000lb stockcar. We use a spec eq head thats only around a 170cc runner. I have tried a 200 runner head and they are very lazy on the bottom end and come on like a bottle rocket about 1/2 way down the straightaway.

I agree the 830cfm carb is WAY to big.