Has any one tested the fit of BB Ford 1.72 rocker arms on a 250-292 chevy? Just trying to get closer to the correct lift without the expense of 292 roller rockers. Thanks.

The ratio is close to the Chevy 6, but the geometry is much different. The Big Block Chevy rocker will interchange with with the Chevy 6 with no problem, its 1.70 stock.

I know its old stuff, but what about some 348/409 rockers. I think they are actually 1.75 ratio? Anybody ever tried (or found) them?

Thanks for the help. The 1.70 knocks my cam from .574 down to .534 but it is what it is. Looks like it's the BBC. Thanks again. Harry

Somewhere I read that the big Fords would work. Has anyone tried them?

I have the proper ratio rockers in high quality stainless steel. 1.75 , same as I run. These are small bodied and will not fatique like aluminum. Also run lots of BBC 1.7. These can be found On my website.

harland sharp sells 1.8 ratio BBC rockers - 16 pack cheaper than you can get a 12 pack of 1.75's.

Beater, I know the Ford 240-300 6 cylinder guys can use BBC rockers of those engines. The share the same geometry as the BBC and can increase their ratio from 1.6 to 1.7 and beyond. Maybe thats what your thinkng about.

56er didn't you say that 1.8s were a hassle to fit?

Why pay 250. for a set that isn't right, when you can pay 289. for a set the has all the perks ( clearance for bigger push rods, Larger spring,1&6 are machined for valve cover clearance, AND has a wider roller tip ) And to top all that off THEY ARE the correct 1.75 geometry in stock.

They were a hassle to fit because of the way I set them up. Also I ended up with 3/8" pushrods, if I had stuck with 5/16" and .110 walls, I would've had even less issues.

I have not worn out my Crane Gold rocker arms that I have had since 1986 ,I think I would have to run a real nasty solid roller to fatigue them, & even then,I think it would be hard make them crack.

You guys can also order individual rocker assy's,dont need to buy a V-8 16 pack.

MBHD

The 292 really needs the 3/8" pushrod more than the 250.

I ran the same crane gold rockers for 17plus yrs And ran them at 8000 rpms. AND I Bought them used from a machine shop after running them on BB on the dyno.I got them for less then half price.back in 84. AND i still have them and would still reused them If i ever had to.

OH and I had them maged and they are still fine.

I'm using a set of Crower stainless rollers 1.75 3/8 stud intended for Chevy six. Required very minor clearance work to the stock valve cover.

I understand the allure of saving a buck. I paid full price for my Crowers and feel it's a good value.

The Crowers are really permanent, first-cabin stuff.
Any aluminum will eventually fail (stretch, then crack), but that's many years if run at moderate RPM and spring load.

My experience is it is the needle bearings that eventually fail, and occasionally a roller tip. YRMV.

well also just for the record The harland sharp rockers Are also a life time guarantee.

Here are some pics.
Comparing a NOS GM, CompCams and a Harland Sharp. All 1.75 ratio. See how much bigger the harland rocker is? I will get weights later. The GM feels the lightest.





Weights
stock 112 grams with pivot ball, 92 without.
Harlan Sharp 192 grams
CompCams Stainless 239 grams

Remember for the roller rockers , only the body moves and not the center pivot. This is where a lot of weight comes from. Have to take them apart to compare pivoting weight.

Tom

So Larry are your Cranes for a BB or L6? Were they running the 1.75s On a BB?

The Cranes where for a BBC 1.7s When i built that motor back in 84 I wasn't going to pass up that deal for 125.bucks for that used set.

I got half of a set (8) of BBC 1.7 Crane Golds for $50. Perfect for the 153. They are used but in great shape. The guy threw in eight more of another brand. Maybe he was running different rockers on intake and exhaust. One of the others is a bit rough.

.... so I guess the answer is no? The big cam motors (400+ hp) used some 300#+ springs and 7/16 pushrods, they ought to be strong enough, maybe not plentiful now a days.

OK. I know this is an old thread but I have a question. When using any of these roller rockers are push rod guides necessary?

I found a Comp Cams stainless roller rocker that is made for the Chevy inline six cylinder, (and the four bangers too). Comp Cams Ultra Pro Magnum XD rockers. My little brother, who had some input into the original design, put me on to them.

For the inline Chevy it's a Comp Cams 1827-1. It DOES require changing to 7/16" studs but I'd recommend doing that anyway. !.75:1 ratio and they are available in quantities of one, eight, or sixteen from most speed parts suppliers. I'd bet you can buy them direct from Comp Cams in quantities of twelve as well.

Little brother uses the BBC version in his Super Stock Camaro. It usually turns 8,200 RPM and it's a four speed car.

Guide plates are normally used with HIGH lift cams. I didn't use them with my 583-607 lift cam And right now I don't have them on this new motor/Cam just shy of 700 lift. And another reason people use the guide plate is with bigger Dia. push rods Because they open up (drill out )the push rod hole. which is pretty much a slot in stock form. When its just drilled out it does not work as a guide very well anymore. When I did my Head I kept it as a slot So I don't feel a Need for the guide plates. But that's me.
hope my 2cents helped.

Thanks Larry, That is exactly the kind off information I was looking for. I thought that was what I was told before but was not quite sure.

A 292 should use the largest diameter pushrods that will fit because of the extra length.

I agree with that. I'm not working on the 292 yet. This is for the 153 finally going together.

Looking at the catalogs, it appears that the Ford rocker is the correct ratio, but the dimensions are different.

The Comp Cams 1827 also fits the 348/409 valve train.

The 348/409=153-292 is also true of the rockers offered by other manufacturers.

These same numbers are NOT listed for the Ford 1.75:1 applications.

Perhaps the difference is in the adjuster thread or shape?

Panic! It could be. If the points of reference, (distance from pushrod to fulcrum, distance from rocker tip to fulcrum, distance from pushrod to rocker tip) are the same you could probably use 'em. If those measurements or the the axis through the fulcrum from the pushrod to the tip are not the same, you'd have to make adjustments accordingly. Even a small variation in these measurements would require that you move the stud or the valve and change the angle of the pushrod! Very small differences might be overcome by altering overall geometry, but if one rocker is much larger or smaller than the other it would be a lot of work and or expense unless you have machine shop access!

If you can purchase the part you need to do the job, why subject yourself to so much aggravation and or expense?? I'd want to have an example of both to do a really close comparison before I'd recommend such a swap.

For example, we used the larger ratio BBC roller rockers on some of our highly modified small block engines. To do so, we had to use offset rocker studs, different pushrod guides, and we had to radically open up the pushrod holes in the cylinder heads to make room for the change.

Another swap is supposed to be Ford Windsor and late Oldsmobile, but I'm not sure well it works in both - only that some mfg. use the same product.

Yep!! The design is really similar, as was the late AMC rocker system. Never tried to interchange any of them, but it's certainly intriguing!