I posted this over at the Dart Forums but I wanted to hear what some people over here would say.

I'm about to step up my stock 881 75cc with 165cc runner heads to a 64cc head. Right now I'm supposed to be pushing a 9:1 compression ratio but I also run a 280 duration cam (comp cams 280h .512/.512 lift with 1.6 full roller rockers). With the 64cc's I'm estimating a base 10.25:1 cr but with the 280 cam my compression in the low end isn't great and I'm thinking that's one of the problems I'm having with a good launch and low end power. I have a 2300 stall in a th400 and 3.42 gears with full length Hooker headers with 1-5/8th primaries and 3 inch collectors. I also have a Edelbrock performer intake (2101). The intake and the cam were installed before I bought the car. I'm basically giving this information just to give you guys an idea of the setup.

I'm was looking at some Dart heads with 64cc and 200cc runners but I think the large runners will bog me down even more in the low end so maybe I should go with a 180cc runner. I want some really good low end torque but still have a decent top end. The piston rings in it are S9090's Total Seal gapless rings that are rated up to 10.5:1 cr so I can't go much larger than the 64 plus I still want it to run off pump gas. Also I'm looking at a Weiand Air Strike manifold that's similar to the Edelbrock Air Gap and flows similar numbers with a little more torque and a little less hp.

 

Your gear ratio isnt helping the situation, does you stall converter actually feel like it is hitting at 2500 rpm at launch? I havnt run any numbers but the 1.6 rockers will also increase the valve lift to .550 and increase the duration making the cam seem even bigger which will hurt you even more with the 3.42 gears. How much work was done to the 882 heads?

 

Yeah, I can feel the stall just barely if I'm trying to launch hard. The 1.6 rockers are already accounted for in the .512 lift (.480 total lift with 1.5's). The 881's are 2.02/1.6 valves and comp valve springs good for up to .525 lift with viton valve seals and stainless valves. The heads are definantly the weakest point and I don't think they're breathing worth a damn.

I went with the stall on both TCI's and B&M's recommendations of my car's weight, cam and engine setup. Both suggested in the 2100 - 2500 range so I went for the middle ground.

In searching for heads I have people telling me to not go over 180cc runners and then others telling me to go for 200+ sized runners.

I ran Pat Kelley's dynamic compression ratio on my current heads and my hopefully future heads. With the new heads it's giving me a dynamic ratio of 8.05 with Pat Kelley saying that, "7.5 to 8.5:1 desirable for a street engine". So I'm right about in the middle which seems good for me and I would assume that would keep me from having any detonation issues. With my current old heads I'm running a 7.25 which is a little below the low end. My S9090 rings are only rated up to a 10.5:1 SCR also so I would still be under that SCR.

 

could be the intake. give elliotts port works a call and see what he can do for you. great guy. knows motors very well top and bottom ends.

 

I'm going to be switching intakes anyway when I move to the setup. Will be going with a Weiand Air Strike 8501 more than likely. There's a place over here not to far from me that I've heard good things about for CNC machining and port work that I'll send to.

Thanks though.