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Quote:

Originally Posted by Rookie (Post 4831212)

Not saying it wouldn't work, I just don't believe it would be the best choice if buying a new cam. If it was sitting on the shelf I would definitely throw it in.
Switched out a straight split cam with one that has a 6° split and it was much healthier and better performing. These heads were optimized and have great exhaust ports. JMO

I wish I had more time to play around with different splits. Had one even split cam back in the day in a 383 surprisingly worked well with GM heads to boot and poor exh. But never compared. Was 16 then… comp 292 magnum cam called (king of the drive in) 😂

I always thought with the more efficient heads and int / exh ratio less split desired but so many factors. When jones spec’d my current ones he chose a 4 deg split. Remains to be seen yet as I’m sure you heard short blocks gotta be torn down and pistons fly cut. (Slight clearance issue but glad we caught it. One engine about read. Got delayed by a good month plus now.

Quote:

Originally Posted by getrdunn (Post 4831298)

I’m sure you heard short blocks gotta be torn down and pistons fly cut. (Slight clearance issue but glad we caught it. One engine about read. Got delayed by a good month plus now.

Yeah, I spoke with Dick the other day about them when I was picking up a friends Pontiac 389 he built and dyno'd. Glad it was caught now.

Quote:

Originally Posted by SB (Post 4831274)

-As you add duration you also add overlap.
-Tightening lobe centers (lsa) does also.
-Amt of Exhaust open degrees past TDC on intake stroke is what really means the most when it comes to reversion possibilities since the exhaust valve still open (but closing) when piston going down drawing in air from both valves (intake valve starts opening before tdc intake stroke) at lower rpms.

Look for some of my cam charts comparing the mag 454/502MPI/ HP500/Crane 731/500EFI/525EFI/Crane 741 and you’ll see seat overlap, .050” overlap (including btdc and atdc), etc, etc. Really good info that if studied, paints great pictures. :thumbs

Good explanation.

Quote:

Originally Posted by ICDEDPPL (Post 4831277)

It`s killing me.
https://cimg3.ibsrv.net/gimg/www.off...de964a2970.jpg

EDIT: didn`t realize this is an old thread .

Did you have a bad experience? I had no problems but I read about many people that did with the aggressive lobes.

Quote:

Originally Posted by jeffswav (Post 4831846)

Did you have a bad experience? I had no problems but I read about many people that did with the aggressive lobes.

You were probably on an OSO break during the lobes and or valvetrain gone bad. I don’t wanna get it all started up however if your comfortable with what you have and lobes look good your likely ok. His concept made since however didn’t agree with many endurance HP builds. Short duration / hi lift ratio a tad off compromising lobes and other valvetrain parts.

Quote:

Originally Posted by getrdunn (Post 4831880)

Well, I had a couple hundred hours on the cam setup. 8 comp roller rockers needed rebuilt or replaced, big time leaks on valves with leak down. It was burning about a quart of oil per day trip. Overall not a horrible experience, but should I pull out the cam or run with it?