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Some of you might recall my tuning issues with 68 KAT's 390. The previous owner did a 1/2 arsed job of deciding what to build and I am still trying to clean up the results.

I know the engine has forged 10:1 pistons, an Edelbrock Performer RPM manifold and a Demon (for now) 750 carb. The heads were port matched and the combustion area cleaned up.

What I am trying to determine (without removing it) is what the cam specs are. The PO and the speed shop that did the work cannot remember anything about it other than it was an 'RV' cam.

Does anyone have any experience with an 'RV' cam on an FE? Is there any way to check it out? I am trying to decide which way to go with it...smaller more easily tuned carb - or aluminum heads, bigger cam and MORE hosepower...

Thanks

Ken
 

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You can use a dial indicator with a 0 to 1.0" sweep and either measure the pushrod travel @ the lifter or the valve. to find actual lift of cam when measured @ the valve you must divide your results by the ratio of rocker arms. on an "FE" it's 1.73 for non-adjustable and 1.76 for adjustable. the only real way is to degree the cam if you do it in the car it's tough because you gotta go through the spark plug hole for your piston stop. but if you take measurments @ 90,180,270, etc you may be able to find some of the data that matches your measurements on a cam grinders web site and narrow it down. or pull the cam and check the numbers and letters stamped on the back and match em up.
 

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RV cams were a popular item in the late 1970's and thru the 1980's. Typical of the genre are Crane's "Blazer" series. You can get a good idea of the specs at (www.cranecams.com).

Any cam that is not stock should be matched to suitable valve springs and the installed centerline checked. 30 year old valve springs are junk even with a stock camshaft for that matter. So many low budget rebuilders reinstall the original valve springs and don't even check seat pressure or installed height.

A 390 Cougar had non - adjustable rocker arms originally so to install a different cam something had to be done about that problem. What was done?
 

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Crane Blazer RV

The Crane Blazer RV is known these days as H-248-2 in the "Powermax" series.
 

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RV Cams

They're called RV cams because RVs (and others of their ilk like tow rigs or other heavy cars) are generally run in the low rpm ranges. They want lots of low end torque to move those heavy rigs. Most of these cams have power ranges of off-idle to 4000rpm at best. Nothing wrong with lots of low end grunt. Cams with 'RV' specs are moderate lift, short duration with minimal overlap.

The cam I'm running in BetaCat is the old Crane Econopower 260. That is just a tad hotter than the 248 Econopower. (The duration of this cam is 260, hence the name). The only reason that I put this particular cam grind in BetaCat was that the original 351'CJ' cam was on its way out, and they weren't available anymore. Now Crane (and maybe others) are making these musclecar-spec cams again. Anyways, the 260 Econopower was very close to the stock CJ cam specs in the lift category, and I don't know about the duration. Ford keeps pretty mum on that aspect. I must have picked a good combination because BetaCat (being almost stock) would run just as fast as AlphaCat that had all the usual performance goodies like headers, Torker intake, 780cfm Holley carb, Crane Fireball cam..... Go figure. AlphaCat was still a low compression engine at the time. Not the best matched combination there.

You have to consider the entire package!
 
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