MK-I MK-II MK-III MK-IV GULF MIRAGE J-CAR LOLA
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Why not start with your first post today and become an active part of GT40s.com now! And, if you find you enjoy GT40s.com think about becoming a Forum Supporter. | | GT40 Tech - Engines/Induction/Exhaust Motors and engine related - right here! |
09-18-02, 11:11 AM
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#21 (permalink)
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Join Date: Dec 1969
Posts: 0
Rep Power: 0  | Re: 302 or 347 ???? BC, if you want the ultimate motor, get a Dart 4 bolt main block (comes in both 302 and 351 deck heights) it will accept much more boring than a stock block (very squared cylinders with much more usable wall thinckness), steel crank, lightest/strongest rods (have the H or I beam debate and what they are made of), lightest/strongest pistons, flat tappet cam (but I would go with mechanical rollers and strong springs if you want RPM and driveability.) The valves have to be big and light (the stongest/lightest material is titanium). Free breathing heads with large ports and an induction system that isn't too long (less torque, but more RPM.)
The only brand I mentioned was Dart because I think their block is the baddest one out there. Ford's alloy block is a very close second in my opinion, followed closely by the sportsman block. For the other stuff, there are tons to choose from, but the goal is keep the stuff that moves as light & strong as possible. You've got to be able to get enough air in VERY fast and you've got to have stong enough valve springs to keep them from floating open at high RPM.
This would cost BIG bucks! Would it be worth it?? I use this analogy: A $50 bottle of wine is much, much better than a $10 bottle. A $150 bottle of wine isn't that much better than the $50 bottle, but it is better! What are YOU drinking?
Bye the way on the Redback Spyder and the Countach they use a Renault transaxle. |
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09-18-02, 05:09 PM
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#22 (permalink)
| | Rookie 
Join Date: Aug 2002 GT40: Frankfurt,Germany
Posts: 86
Rep Power: 7  | Re: 302 or 347 ???? It doesnt quite feel like 250+ hp, but it is probably a little misleading as the max hp is perhaps around the 4000rpm mark and only proper gearing would turn the power into speed. I compare it with my everyday car, a chipped Audi 1.8T which does 150mph with ease with just under 200hp. Gearing is nearly identical with the 40 - same rpm/ same speed but I want my 40 to beat the Audi.
With not too many options on gearing, I think the engine has to be made to rev.
I think I will put it first on a dyno to get a reference and then do some surgery over the winter months. I would be quite comfortable with 300-350hp but they should be at higher revs. |
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09-18-02, 07:58 PM
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#23 (permalink)
| | 40bud 7 Tenths 
Join Date: Nov 2001 Location: San Francosco a GT40: GTD Finished in
Posts: 710
Rep Power: 15  | Re: 302 or 347 ???? I think you would be suprised at how much improvement you good get with some head work and a cam. Increasing the valve sizes in a stock small chamber head to 1.94 intakes and 1.6 exhaust plus gasket matching both intake and exhaust and a little clean up of the ports around the valves will do wonders. Add some good double springs to work with a nice cam and some Crane Hi Intensity lifters and you should be able to turn more revs than is wise for the bottom end. I have a similar set up and have accidently exceeded 7500 at the drag strip. I also use an after market intake manifold ( Offie 360 ). A little work but not a lot of money. I use a Crower split pattern cam with >486 int. and .498 exh. lift and duration @ .050 of 220 int. and 228 exh degrees. I hope this will help. |
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09-18-02, 08:08 PM
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#24 (permalink)
| | wbmusarra 10 tenths 
Join Date: Oct 2001 Location: Snellville, Ga. GT40: DRB#5
Posts: 1,180
Rep Power: 20  | Re: 302 or 347 ???? A great source for working with the Windsor is FORD WINDSOR SMALL BLOCK PERFORMANCE, parts and modifications for high performance street and racing by Isaac Martin. It covers 302/5.0L and 351W/5.8L Ford Widsor Small Block Engines. A virtual gold mine of parts and part #s. Hard to put down once you start reading. [img]images/icons/smile.gif[/img]
Bill |
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09-19-02, 05:04 PM
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#25 (permalink)
| | Rookie 
Join Date: Aug 2002 GT40: Frankfurt,Germany
Posts: 86
Rep Power: 7  | Re: 302 or 347 ???? Thanks, guys, this is a good starting point. I also will get the book. What compression ratio would you suggest? What pistons? |
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09-19-02, 05:43 PM
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#26 (permalink)
| | Neal 8 Tenths 
Join Date: Sep 2001 Location: Seattle, WA, US GT40: GT40 NZ
Posts: 858
Rep Power: 16  | Re: 302 or 347 ???? You should be able to safely run 10:1 with Aluminum heads or 9 to 9.5 with iron heads.
Hypereutectic pistons are OK for mild use and less expensive. Go forged if you want some extra margin or plan to hammer on the beast. You are limited to a .030 overbore on newer 302 blocks leaving you with a 306ci displacement.
The Ford B and E roller cams are popular and make decent power.
Another useful book is Building Ford Short-Track Power by the Ford Racing folks. |
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01-03-04, 04:48 AM
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#27 (permalink)
| | Des Bronze Supporter 
Join Date: Jul 2002 Location: Eukey Qld OZ GT40: WPS GT90
Posts: 148
Rep Power: 9  | Re: 302 or 347 ???? There is a red DRB which has a Lexus v8 in it, it apparently is putting out 220kw at wheels with no mods other than aftermarket computer. Goes well, sounds different but most of this is probably due to 1 pipe per bank exhaust (no crossover)
Regards Des |
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01-05-04, 05:03 AM
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#28 (permalink)
| | Rookie 
Join Date: Jan 2004 GT40: sydney australia
Posts: 13
Rep Power: 5  | Re: 302 or 347 ???? i have a 347 making 450rwnm of torque,235rwkw or 315rwhp(based on australian dyno's @ 30%loss or 369rwhp with a 15%loss as per us dyno's)
@6200rpm.
I would go a 347, you dont have to rev them hard to make good power for the street. |
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