I'm in the process of rebuilding a 292, I just pulled the rocker arms off my old engine and found them to be "5751066". According to ford-y-block.com, these are 1.43:1 ratio. In my research I have done I have found that the 1.54:1 rocker arms are the ones to have. Is this true? Or does it simply depend on the engine you are building and for what purpose? I am trying to build a 292 for a 59 fairlane/galaxie 4-door that will have a little more power than what it came with. Perhaps some day I will try and make a true power house y-block, but for now it will simply be for cruising. All that said, will it matter if I run the 1.43:1 rocker arms versus the 1.54:1 arms? If so, how much? Any advise would be greatly appreciated. Thanks in advance for any help.
Yea, what yblock32 said, And in general yes the 1.54's will show you some improvement. as with most things hot rod it is the individual little things that mount up.
It depends on several different things. This may end up to be more information than you wanted, but I'll try to make it reasonably coherent. If you chose (for example) a cam that had, say, .500 gross lift at the valve, you don't actually get .500 lift. A Y block has solid lifters, so you must subtract the lash...say .022, which takes you down to .478. If the cam designer originally planned the profile to be used with 1.54:1 rockers, and quoted the specs that way, then obviously, if you used 1.54 rockers you'll get .478 lift. Under those same conditions, if you ran the 1.43 rockers you'll get .443 lift (after lash is subtracted). It's not quite as easy to figure what power loss you might get from doing this. A lot of people will tell you that "more rocker ratio doesn't increase duration". This isn't exactly true...while the gross duration isn't really changed, at any particular given lift the duration is slightly greater...in other words, there is more area under the curve. So it is possible to lose some power by using a lower ratio rocker...under certain cir***stances. Somebody's probably gonna chime in and misinterpret that statement- but there are times when a lower ratio arm actually will work better, and times when a higher ratio works mo' better. Now, here's the rub: many cam specs are, or were, given using ratios that have no relationship to the actual available rocker arms. At one point in time, many specs were calculated with a 1.5:1 ratio, regardless of whatever the engine itself had...in certain cases, cam companies would actually offer their own rocker arms for an engine, in a 1.5 ratio, to avoid problems. The reasons why this was so are a long story for another time...I mentioned it because a lot of H.A.M.B.'ers use old NOS cams from Gawd knows when, and it's important to understand what you are getting. The bottom line is this...just going by what you've described- a mild 292 rebuild with slight power improvements- you probably will not notice much difference either way, if you did a true back-to-back comparison. If you have rocker ***emblies that are in good shape (which most Y rockers aren't), I probably would spend your hard-earned money on other things. If you need to replace them, get the bigger rockers (which are available new, actually). Some other areas to look at first, IMHO: 1) Compression (most common 292 Y rebuilder pistons sit very low "in the hole" at TDC, and typically the compression ends up to be very low, especially with large-chamber heads. There are a couple of solutions to this.) 2) Use the later ECZ-9425-B intake manifold with a Holley 390, 450, or 600 vacuum secondary, or an Autolite 4100 carburetor, and take the time to tune it. The 4100s are dirt cheap, usually; Holleys are much easier to tune and there are several good books covering exactly that process. 3) Y block exhaust manifolds ****, or rather, they don't. Most cars won't accept the rams' horns exhaust manifolds, which are kind of expensive. Use good long-tube headers, or at least try to clean up the casting slag and smooth the transitions in your manifolds. 4,5,6,...) Use a decent distributor! !! Since many Y blocks are a mishmash of parts by now, it is possible that you have just about anything, including a Load-O-Matic, God forbid. Go to Advance Auto Parts (the cheapest source last I checked), or NAPA, AutoZone, etc. and buy a rebuilt distributor for a '64 F-100 with a 292 engine. (Other applications may or may not list a distributor, so it's just easiest this way.) Then, again, take the time to tune the distributor's advance curve. If you aren't familiar with the process, look for a local shop. BTW, you can easily convert this distributor to electronics, as there are several kits available...Pertronix, etc. if you want. You might also consider talking to GMC BUBBA here on the H.A.M.B., who does this sort of thing on a regular basis, has a distributor machine, and seems to have pretty reasonable prices. He generally has period-correct pieces on hand, like Roto-Faze, Spaulding, etc. if that's what you need. Long post but hopefully it helps a bit.
The 1.54 rockers are rare and new ones expensive. If you are building a street motor, spend your money elsewhere. Find some G heads, open up the exhaust side some, nice cam, good ignition, good intake, and the flat top exhaust manifolds. Feel free to email me anytime, I currently have a 312 going together.
I agree with Ole Don too . If you have good "G" heads or big valve heads and a good aluminum 4bbl intake then that is a good start to let your engine breath with . It really depends on what you want from your Y block . If you want something for the street that sounds noce then that is not hard to do . Now if you want more performance then you can expect to pay much more money to get that . Look on John Mummert's wed site and that will help you understand many things about the Y block plus he has some good performance parts and great machine service to get more out of your Y block . He also have some very nice strocker kits at good prices too ! Ted Eaton is another very good machinist for the Y block . It all depends on where you live to get to these two people . You really can get some good HP from a Y block but more HP means deeper pockets . As for rocker arms there are very good roller rockers made for the Y block ! If you need any more information or help , just ask and send a PM . Retro Jim
thanks for all the advice. I already have the 4-barrel manifold (ecz=9425-b), my heads have been redone. but, I have been told that putting a 312 crank in there that greatly improve my chances. Any ideas or suggestions would be awesome. just let me know.
"Improve your chances?" Sure you can just "put a 312 crank in there" but first gather up 1500 to 2000 bucks for machine work and parts. here's mine, a very old thread on yblocks forever. 292 stroker
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