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another big block rocker arm question

Posted By: lildevil1972

another big block rocker arm question - 01/10/09 02:17 AM

okay so i am building a 512 low deck with victor heads and i have hughes 1.6 rockers. I am running a roller cam with 681/705 lift with 1.5 rockers. The valve springs i think i am gonna run have 735 pounds open pressure. I can't afford to buy harland sharps this year and am hoping to run the hughes rockers for this year then switch to harlands next year do you think i will get away running the cheapos for a year or am i setting myself up for problems. The hughes rockers are only a year old.

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Posted By: Anonymous

Re: another big block rocker arm question - 01/10/09 03:40 AM

I would scare me...A broken rocker or adjuster can be a disaster...

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Posted By: Cab_Burge

Re: another big block rocker arm question - 01/10/09 06:13 AM

Call Hughes and ask them what they recommendations are on their rockers for max spring pressures
Posted By: DaytonaTurbo

Re: another big block rocker arm question - 01/11/09 01:33 AM

Quote:

Call Hughes and ask them waht they recommend on their rockers for the max spring pressures




That is a LOT of spring pressure, I would check before trusting them to that level.
Posted By: brktracr

Re: another big block rocker arm question - 01/11/09 03:28 AM

A broken rocker just cost me a bunch of money. Only 16 passes on a brand new motor, didn't replace my rockers. One exhaust valve broke during a pass creating tremendous cylinder press because the intake still sucking air in and no way to exhaust. Hurt a bunch of parts. Now I'm building another new motor. Just something to think about.
Posted By: Streetwize

Re: another big block rocker arm question - 01/11/09 03:28 PM

Too much pressure

how much HP are you looking/expecting to make and what kind of RPM are you wanting to turn?

For a non mega-block shortblock app even with a girdle and/or good caps I'd try to stay around the 680-720HP PEAK range and with good heads you don't need that much cam to get there, I don't know the whole combo you are planning but remember the bigger the cam the higher RPM the torque/power peaks will be which means the stress levels on the block raise proportionally. A well machined low deck can handle more power but even still the heavier the car the more load you're putting on it if you want it to last.

Yuo want power and reliability but when you push too high it's tough to get both...you'll going big with the cam so that means you gotta be willing to drop the coin on the valvetrain....I consider that kind of build a time-bomb and if I know ther's that kind of "big power but skimping on the good stuff" in the other lane....I wouldnn't want to stage next to them....Ex: there's hundreds of 500+hp 5.0's out there that won't drop the small coin for c-clip eliminators in the rear-end...can't tell you how many times I've seen an axle fly out of a 5.0 and the car wind up in the other guy's lane!!

Don't mean to sound harsh but I'd like you to think that one over cause with roller motors all bets are off what happens to your motor (and your car) if something internal lets loose. Don't skimp...i think 70Blackfish is selling a set of offset T&D's with roller fulcrums on Moparts Racing parts right now.
Posted By: Anonymous

Re: another big block rocker arm question - 01/11/09 10:09 PM

Quote:

Too much pressure

i think 70Blackfish is selling a set of offset T&D's with roller fulcrums on Moparts Racing parts right now.




is he selling them because they didn't work well with the victor heads????????
Posted By: Streetwize

Re: another big block rocker arm question - 01/11/09 10:32 PM

That may be....

The issue is when you combine a Max wedge aluminum Port with a Low deck AND a Roller cam the pushrod is so short that the pushrod angle is going to be pretty severe (compared a taller RB with a conventional flat tappet) You can opt to go with the offset lifter or relieve the pushrod cuts inthe heads (which I what I did on my similar motor.
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