to thump or not to thump?

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ltrripp11

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gentleman

got a newly built 416 stroker from a 340 that i need cam advice on. the motor currently has the comp cams xe 268/280 477/480 lift cam in it. however ive been told by a number of people this may be a little small for my combination? i got it prior to deciding on 416. car runs good but dont seem as strong as it should be? in any case im leaning towards the edelbrock performer rpm cam 308/318 480/510 lift simply because i already have there manifold to compliment it. that being said im not sure ill get the lope i want at idle with that? whats your thought? therefore im toying with the idea of the middle thumpr cam 287/304 497/483 lift. i need to get it right the first time cuz once its in its in. ill list my current package...

416 stroker eagle crank
eagle h rods
the above cam
diamond pistons 9.4.1 compression
factory x heads ( may change up to performer rpm later date?)
354 rear gears
27 inch rear tires
727 factory trans
unknown size of convertor but most likely stock spec.

this is not going to see a race track. just want a strong street package. one last item is above 200 degrees engine temp i will get detonation on full throttle with a conservative timing set and premium fuel. would a longer duration (bigger cam) help or hinder this? ok this is your motor. what would you choose based on your knowlege? thanks in advance.

B.T.W. anyone suggest a good solid performance shop in the boston area that deals in mopar maybe?
 
Detonation above 200 degrees could very well be a poor cooling system i.e. radiator. Case in point, totally stock rebuild spec 318 2 brl. I fought detonation for weeks. Various heat range plugs, different fans, nothing helped. New radiator cured it.
 
ok after much research and calls i went with the comp thumpr cl20-601-4 with 287/304 duration and 497/483 lift. thanks redfish...
 
Maybe it's just me, but I would also upgrade your converter if it is stock (even with a strictly street car). Go with something a little higher stall than stock and it will make a huge difference, you will not be disappointed. It will get the engine into it's powerband rather than holding it back.
just my opinion.
 
ltrripp11 said:
ok after much research and calls i went with the comp thumpr cl20-601-4 with 287/304 duration and 497/483 lift. thanks redfish...
Click to expand...

Still seems small to me, those lift figures aren't much bigger than the lobe lift on my cam lol. Personally I would have went with something like 248-250 duration at .050 and .530-.550 lift. Now that would thump.
 
Your detonation issues are the result of too much cylinder pressure because the cam is so small. If it was my car, I'd be look at the Crane 694561. Pushrod selection is crutial for proper preload, but it will run with stock rockers. Prob ought to upgrade the shafts tho, or simply upgrade to a set of mechanical rockers. But that's what I'd run in my own.
 
thanks moper. had a feeling that was part of my detonation issue... anyways went with the mutha thumper and a 2500 stall converter from hughes. thanks to all.
 
Tell us how you made out? Big difference? How do you like it from previous set up? I'd agree the XE268 is on the small side, but should have still given you good power, but what is "good"? Again, let us know how you like the new combo...
 
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