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Motor/Carb Questions


Whitey741

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Given the late model rule changes at HMP, I have a couple questions about motor/carb combos.I know there are a lot of variables but generally speaking.

 

From what I have heard the 604 crates are putting out 430HP+/- How does that compare to an "average" 2 barrel motor. How about an open motor with the 390. I know money buys HP. I know a buttload of HP can be made with a 390. But at some point, money has to play a large factor in how much can be made with the carb limitation.

 

How much difference (if any) would it make if you went from a two barrel to a 390 4 barrel. Reason I ask since the open motors are now allowed in the PLM class. is it even within the realm of possibility that a good 2 barrel motor with a carb change to a 390 would be able to over come the weight and left side percentage disadvantages and be even remotely competitive?

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I ran a 2bbl last year and put a 390 on it for the spectacular. The first thing I noticed was the extra power unhooked the rear quicker than the 2bbl. But the 2bbl didnt seem to pull as hard. Im not a motor man, just giving you my observation.

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When we ran TAMS we ran a 4412 2 barrel motor. It made about 450hp. We finished 2nd in points with it. Just before the modifieds folded under USRA we put in a 850hp 434 cid alum headed motor with 850cfm carb. You couldn't ever give it over 1/2 throttle. Our Romco motor was an alum headed 9:1 motor with a 390. It made 643hp, but it also cost over $20K to build (and it's still sitting in my shop because no one will pay what it's worth). I'm not even considering pulling our crate out and putting it in. As I said in another post, the current rule revisions strongly favor the 604 crate. If they give some more left side and a little less weight (mainly left side %), I might reconsider.

We ran at Motordrome and Jennerstown, PA and they have rules that let you run anything from a 602 crate to a full blown SLM motor and they had the rules so well tweaked that you couldn't predict from week to week which type of motor would win.

If you want to be competitive, stick with the crate or lobby John & Jack for better unlimited rules.

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