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I know, another please help me choose a cam thread, but any help would be greatly appreciated. I am in the process of rebuilding my 75 L48. I have the TH400 with stock converter and 3.55 rear end. I am planning on the Dart SHP aluminum heads (http://www.summitracing.com/parts/DRT-127122/) and and Edelbrock 2101 intake. The block will not be bored out, only honed, and I will be using the stock pistons. Additionally, I will be taking out the egr, cat and y pipe and running straight duals. I will, probably next year, be converting to an OD transmission, just not in the cards right now.
My goal for this is to maximize power and torgue in the low to mid range. I don't intend to race the car, but would just like to have a fun and shall we say spirited driving experience around town. I anticipate spending somewhere in the $2000 range.
At this point, I have narrowed my choices down to the following:
I have obviously decided to do a roller conversion, but between the available choices, I'm not sure what I get and loose with each.
Thanks in advance for any help you can offer.
I'd go with the first one. You may find it a bit sluggish from a stop due to the stock converter, but I take it you will get a slightly looser converter when you go with the OD tranny? You want about 2000 rpm stall with that cam.
I'd go with the first one. You may find it a bit sluggish from a stop due to the stock converter, but I take it you will get a slightly looser converter when you go with the OD tranny? You want about 2000 rpm stall with that cam.
Define sluggish. What is the stall of a stock converter?
What would make the middle one your choice? If I understand this correctly, which is questionable, then the middle one would give me somewhat better performance off of the line but would sacrifice a little at the top end. Is that close?
I would use the first one and a 1094 head gasket to get as much compression as possible. With 64CC heads you will be @ about 9.4 to 1. The Corvette with TH400 has a stock 2000 stall convertor. That and 355 gears you will be fine. No problem off the line.
What would make the middle one your choice? If I understand this correctly, which is questionable, then the middle one would give me somewhat better performance off of the line but would sacrifice a little at the top end. Is that close?
Yeah, that's pretty much my rationale, but I'm conservative about camshafts when using an automatic transmission. I'm not really what you'd call an expert, either, to be honest. 63Mako says the th400s came with 2000 rpm stall converters, couple that with your 3.55 diff gear, and also that it's a roller, which gives it a wider powerband than a flat tappet cam,and yeah, I guess I'd go along with the first cam choice.
Somewhere in my pile of paperwork I have a GM spec sheet on the 72, the TH400 used then had a stall of 2000. I've never found any other spec sheets on it.
Rule of thumb, your bottom number of the operating range of the cam you want at least 200 RPM below the convertor stall. If your car was a 350 turbo with a 3.08 gear I would point you toward a little smaller cam. Your heads will better realize their potential with .500 lift and more duration if your gearing handles it which it should.