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#92643 10/11/17 12:05 AM
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I just picked up two cams with a bunch of 230-250-292 parts but can't tell what they are. I was told they are mechanical. The Crane looks like a HMV-272 but also look like it's been stamped twice, is it a regrind?

Looking to get specs and best application on both.

Thanks




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I wouldn't worry about a double stamp, regrinds usually have the original numbers obliterated with a series of XXXXX's over them. Are these cams ground on 194-250 blanks or 292 blanks. That can deter how they are used somewhat?



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They're both 194-250 cams.

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I pulled this info on the Isky cam off Summit Racing:

Brand:Isky Racing Cams
Manufacturer's Part Number:231525
Part Type:Camshafts
Product Line:Isky Oval Track Solid Flat Tappet Camshafts
Summit Racing Part Number:ISK-231525

Cam Style: Mechanical flat tappet
Basic Operating RPM Range: 2,000-6,000
Intake Duration at 050 inch Lift: 228
Exhaust Duration at 050 inch Lift: 228
Duration at 050 inch Lift: 228 int./228 exh.
Advertised Intake Duration: 268
Advertised Exhaust Duration: 268
Advertised Duration: 268 int./268 exh.
Intake Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio: 0.525 in.
Valve Lift with Factory Rocker Arm Ratio: 0.525 int./0.525 exh.
Lobe Separation (degrees): 109
Intake Valve Lash: 0.025 in.
Exhaust Valve Lash: 0.025 in.
Grind Number: 525-A

But this one is a 525-B, is there a difference?

Last edited by chevy2inreno; 10/11/17 09:39 PM.
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OK, looks like I found the info on the Crane:

Part Number: 204541 Grind Number: H-272-2 (REPLACES HMV-272-2)
Engine Identification:
Year Range Make Cyl Description
62-84 Chevy 6 Good low to mid range torque, good idle, daily usageand off road, towing, performance and fuel efficiency,2600-3000 cruise RPM, 8.75 to 10.5 compression ratioadvised.
Engine Size
194-250 C.I.
Valve Setting: Intake - 0 Exhaust - 560 Hot/Cold - HOT
Lift: Intake @Cam 3027 @Valve 530 All Lifts are based
on zero lash and theoretical rocker arm ratios.
Exhaust @ Cam 3200 @Valve 560
Rocker Arm Ratio 1.75
Cam Timing: TAPPET @ 0.004
Lift: Opens Closes ADV Duration
Intake 25.0 BTDC 67.0 ABDC 272 °
Exhaust 75.0 BBDC 29.0 ATDC 284 °
Spring Requirements:
Part Number 99838
Loads Closed 112 LBS @ 1.65 or 1.65625
Open 327 LBS @ 1.12
Recommended RPM range with matching components
Minimum RPM 1800
Maximum RPM 5400
Valve Float 6000
Cam Timing: TAPPET @0.05
Lift: Opens Closes Max Lift Duration
Intake 1.0 BTDC 35.0 ABDC 107 216
Exhaust 51.0 BBDC (3.0)BTCD 117 228

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Now, which would be best for a 250 with 307 pistons, lumped head and a 4 speed in my 63 Nova?

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I guess the question would be: How much would you put up with a temper mental engine?
The second cam looks to be hydraulic lifter, maybe you could use some Rhoads lifters to calm it down some. It will have a pretty good idle with standard lifters.
The 1st cam is a smaller grind and should idle great. Only problem is the solid lifters.


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65 Chevelle Wagon and 41 Hudson Pickup
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Part of the decision should be your "crawl ratio", which is 1st gear X axle ratio.
If the product is 10 or more (2.52:1 Muncie X 4.11:1 axle = 10.4), either cam will probably be acceptable.
If the product is substantially smaller (2.20:1 close ratio box X 3.08:1 axle = 6.8) the milder cam will be easier to live with. If you choose the hotter cam a heavy flywheel will make stop lights less annoying.

panic #92662 10/13/17 01:30 PM
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Originally Posted By: panic
Part of the decision should be your "crawl ratio", which is 1st gear X axle ratio.
If the product is 10 or more (2.52:1 Muncie X 4.11:1 axle = 10.4), either cam will probably be acceptable.
If the product is substantially smaller (2.20:1 close ratio box X 3.08:1 axle = 6.8) the milder cam will be easier to live with. If you choose the hotter cam a heavy flywheel will make stop lights less annoying.


Yeah, my factory 3.50:1 Saginaw x 2.73:1 axle = 9.3.

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Thanks for all the input. Helps a lot.

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Chevy2
I don't have your car in the Gonkulator database ie gears, exhaust, weight etc so I just grabbed a 255cid from Tom Lowe's old dyno series & shoved your cams in there. 255cid, Clifford intake, headers, lumps/ported head, 9.45cr.

Isky
Torq 285 at 4300
Powr 294 at 5900
Best at 2-advance or 107i 111e

Crane
Torq 285 at 4200
Powr 286 at 5800
Best at 1-advance or 111i 113e

In other words, "about the same" so it's down to, which do you have lifters for, whats your lift limit, car specifics, etc.
And are you ready to turn 6000 or else they are both too big

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Thanks for the additional info. The car is a 63 Nova wagon with Super T-10 and 4.11 rear.

How would those cams work in a similar 292?

Thanks,

Dave

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When the displacement is enlarged the engine needs more cam events, so it will feel milder with a 292.

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Ok 63 Nova Wagon, should be about 3200 lb including driver, gas, tools, and maybe a dog bed.

The Isky was slightly stronger over all though it may have a rougher idle. I put the engine above in your car, 2" duals, and here we go. This is at sea level, so up in Reno it will go slower:
Torq 285 at 4300
Powr 294 at 5900
Shifting at 6000, again kinda high unless set up for it
2.16 60ft
9.21 at 75.8 1/8 mi
14.34 at 96.80

I also Gonkulated a 292-30-over, everything else same:
Torq 331 at 3800
Powr 312 at 5500 also really high for a stock 292
2.10
9.00 at 78.1
14.00 at 97.8
The 292 is faster of course, but with all those gears it's not too much advantage and about 40 lb heavier.

My test mule is a powerglide car (very consistent launches with a 3.08 gear LOL), and the 292 makes a huge difference with that tall gear. You've got a steep enough gear that it's not that different. As Panic pointed out it will idle better, peak lower, but then again it better because the 292 doesn't like revs.

I have a stock 292, but I'm not sure I would dare ever go over 5000 with it. That's probably extra safe, but that's how I keep my budget low!

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Very cool. Thanks for taking the time to run the numbers.


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