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502 efi upgrade

Old 10-22-2007, 09:30 AM
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Originally Posted by articfriends
The butterflys are custom made in a larger diameter to match the bored out throttle body,it was worth about 10 hp/ft lbs of tq acrossed the board running my 540 N/A on the dyno,Smitty
Smitty,

Can I buy a throttle body which is ready bored and with the bigger butterflys.
You can e-mail on [email protected]

Harry
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Old 10-22-2007, 05:47 PM
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I have to find the sheet. there is a whole recipe for doing the engine. will basically be a 500efi when you are done. runs real well and dependable. don't ever let anybody tell you that you can put a bigger cam in & not remap. maybe you can but I don't think it is wise. the remap costs about $400 last time I did it.
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Old 10-22-2007, 10:46 PM
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WHo are the better names in remapping. I'm going to use a "731" cam.
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Old 10-23-2007, 05:43 PM
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cam I used was 169621.
Use Mark at Precision Marine for programming your efi. He is as good as they get. If you want to remap I would suggest a tried formula unless you want to send your engine out for dyno time & custom tuning.
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Old 10-23-2007, 06:38 PM
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That cam is very similar to my 168731
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Old 10-23-2007, 10:58 PM
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So who do i contact for a remap?What would be a good cam without having to change whole drivetrain on both engines?Exhaust Manifolds are first on my list and mirage plus 25p props.Sill dont know if Gil is much better than Emi Thunders?I can get a good deal on Emi's.
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Old 10-24-2007, 08:33 AM
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FYI...I have had my stainless marine exhaust for 6 years. Still like new.
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Old 10-26-2007, 07:43 AM
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I also like the stainless marine. I have it on my own boat & alot of others I know of. Nobody has leaks. just make sure you get longer tailpipes than the stock-like short ones for any type of high performance engine. I can also get the remap, machining, or any other parts or services for you for the upgrade.

Jim
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Old 10-26-2007, 07:51 PM
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So far Stainless Marine seems to be a favourite in this thread although from research on the internet it seems like Gil is most popular.Their runners are supposed to go all the way down the tailpipe from what i understand.I cant seem to find any info on the EMI thunders as to what they are built like on the inside.Are they just an open chamber Manifold or do they have internal runners?I hve decided to stick with stock 502 mags but im gonna get manifolds and risers this year.Next year i can still do some performance work once i get some more cash
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Old 10-26-2007, 09:03 PM
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If you buying rotating assembly you could make it a 540. You bore the block .030 over and make it a 4.500" bore with a 4.250 stroke. Use the Crane 168741 cam. I did this and used the stock fuel injection and the motor made around 600hp.
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