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assume for a minute that I want a target HP/torque target of 350-400 each. obviously, it will take a more radical build for the mouse, as opposed to the Rat, correct? my question is, which would provide the better overall ride and MPG, the milder Rat or the radical Mouse?
Better ride and MPG would most likely be mouse. But the best substitue for cubic inches, is MORE cubic inches ;)
The rat has more raw power potential and is easy to get horsepower out of...if you can afford the parts for it. Plus the SOUND of those monstrous valves thumping away is hard to match.
My rebuilt which I am picking up Monday is 350hp and 380 torque at 5500 rpm.
I do not know very much about rodents, but think the differences in the question you pose are quite small. There are so many variables in a rebuilt that it is difficult to pinpoint exactly what the final power will be.
Please take in to stong consideration that I have never earn a nickle as a mechanic. So, just my opinion. :)
From: Just because I'm paranoid doesn't mean people aren't out to get me...
St. Jude Donor '09
Re: Rat or Mouse? (OHSIXX)
Even at 2500 rpm a moderately built rat will put out 400ftlb of torque and increase from there. The torque curve is a flatter on a BB. A hi-po SB may reach 400ftlb but that'll be it's "peak".
The stock spec on the '87 BB I'm rebuilding now was 387ftlb! :eek: And that's on a smogged, low cammed, iron headed, dished pistoned engine. :crazy:
ok.. I may not have been clear.. if I were to build a 350 and a 427.. BOTH to hit the exact same HP/torque, in aprox the 375-400 range, would the 350 be more economical? it would require a much more radical cam profile than the 427.
My stroker was built to put out @ 490hp with a more aggressive cam in the low - mid 500's. That being said my power comes on in the high rpm's. I do however average 18 - 20 mpg, but bottom line, ain't nuttin' like a bb, with it's stump pulling torque. Just can't beat cubic inches. :yesnod:
ok.. I may not have been clear.. if I were to build a 350 and a 427.. BOTH to hit the exact same HP/torque, in aprox the 375-400 range, would the 350 be more economical? it would require a much more radical cam profile than the 427.
If both engines were used in the same car, same gears, tires, etc., the sb would probably have a slight fuel economy advantage because it would need less fuel to power itself and the car would weigh less. However, if the BB were combined with taller gearing to take advantage of it's greater low end power, it may well get better mileage. If economy were the main criteria though, the sb would be much less expensive to build because it's parts are a lot cheaper. Even if the BB did wind up with a fuel economy advantage, it would probably take a few hundred thousand miles before enough fuel was saved to reach a break even point.
well, it's a case of having my cake and eat it too. I want decent power, but to get the figures I want, a mouse may very well need a fairly radical cam. I am trying to get the optimum balance of power, drivability and economy I can get
If you are on the fence, I would say you will be happiest keeping the small block. Much less to change, less hassle, and still great power. I am very impressed with the hydraulic roller cam in my ZO6. It will hold its own against most BB's even considering torque and still get great mileage. Certainly it has better heads than a standard small block; but, you could still get very close with high flow aftermarket heads, good carb, and free flow exhaust system.
IMHO 375/400 torque & hp isn't that radical anymore for a sbc. The parts and knowledge have come a long way since the early 70's high compression LT1's. Look at Edelbrock's RPM package putting out 400+HP with 9.0:1 compression on pump gas.
When switching to a BB, keep in mind you'll also have to switch the exhaust, pulleys & brackets for the assesories(sp?) and possibly update the cooling system and front suspension for the added weight.
If cost isn't a concern, a BB between a C3's front fendors is an AWESOME site. But for what your goal is a sbc should suffice :yesnod: . :)
If cost isn't a concern, a BB between a C3's front fendors is an AWESOME site. But for what your goal is a sbc should suffice :yesnod: . :)
That's what I was thinking too.. I was just wondering if the BB with a mild cam would get significantly better mileage. of course I think a good rebuild, a modern intake, headers and exhaust will make the SB respectible, AND get a boost in MPG over the '82 standard