Corzette Posted March 1, 2003 Share Posted March 1, 2003 HEy guys I have finally got all my parts ordered and car home...except for the push rods. The Summit guy told me that I need to measure for pushrod length. I have no way of doing that. Here is the setup: 1975 SBC 350 retrofitted with the Comp Cams XR282HR-10 and roller lifters and full roller rockers 3/8 in studs. I have a 3.48 standard stroke with 5.7 rods. Does anyone know what length pushrods I need would be? Grumpy could you help? Thanks in advance..... CorZette Japan Quote Link to comment Share on other sites More sharing options...
John Scott Posted March 1, 2003 Share Posted March 1, 2003 Most likely you'll have the stock length, 7.8". Aftermarket heads, rockers cams can all change geometry even if only slightly. Rule of thumb is to have the roller tip in the middle of your valve stem at 1/2 of you cam lift. This is after setting your valve lash solid cam (cold) to specs first. A good eyeball can verify the tip is the same distance from centerline closed as it is away from centerline at full lift. Comp cams has a good article on this in their tech help area. http://www.competitioncams.com/information/Products/Pushrods/ They also make a fool proof push rod checking tool that changes length a predetermined amount per revolution, .05. I used the pn 7703-1, push rod length checker #3 for standard and longer. If you don't want to purchase one you can borrow mine. I shouldn't be needing it until next engine. Check out the cc site and read the tech. E-mail me and I'll be glad to send it to you. Another tip, trick flow makes a good one piece cold formed 4130 pushrod .080 thick, chamfered holes for less than others. Sizes are etched on the sides for easy verification. PS>Rereading your post I see your cam is hydraulic, so might require a solid lifter of same length, or perhaps a super light valve spring to check accurately. I honestly am not sure how its done with the hydraulic lifter. I'd call your cam company for length and checking recommendations. John Quote Link to comment Share on other sites More sharing options...
Mike C Posted March 1, 2003 Share Posted March 1, 2003 That Comp site is a good place to start. Most of the big valvetrain makers sell pushrod length checkers that involve an adjustble pushrod. Another option is a Proform or manley length checker. It is a pseudo rocker made of plastic. You put everything together with a stock pushrod. drop the plastic rocker on. If there is a gap between the pushrod and rocker, measure and buy that much longer pushrod. If there is a gap between the valve, buy that much shorter pushrod. About $15 from the mail order places. Quote Link to comment Share on other sites More sharing options...
Mudge Posted March 2, 2003 Share Posted March 2, 2003 I have standard length 7.8" Chrome Molly pushrods that I dont need, they'd go for cheap if you want them, then let me know, doh! Your overseas, if you have a local place that would probably be better for you. Unless you've shaved the heads basically you use stock length pushrods. Quote Link to comment Share on other sites More sharing options...
John Scott Posted March 2, 2003 Share Posted March 2, 2003 Unless you've shaved the heads basically you use stock length pushrods. Mine ended up needing .200 longer than stock. Heads brand new, cc pro mag rockers. Perhaps it was the cam base circle? Was block decked? I wonder how a plastic rocker arm can verify the differences is rocker ratio, or even make to make. I battled different rockers of different make i.e. Alum cc, harland sharp, crane on my Dart Pro1s of same ratio either hit or cleared retainers, and had different contact area on the stems. They don't all sit the same on the studs. My AFRs use CC pro mags, formerly (Hitech) one of the best for weight and durability IMO. I'd use the pushrod checker with the rockers to be used. John Quote Link to comment Share on other sites More sharing options...
grumpyvette Posted March 2, 2003 Share Posted March 2, 2003 heres a simple way to get close to the correct length BUY ONE OF THESE http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=3567&prmenbr=361 after making sure the valve springs are correctly installed you drop the checker in place on the rocker stud and install your adjustable pushrod adjust the length to fit and measure the resulting length if its within twenty thousands of the stock length its fine for most applications, if its more than 30 thousands long or short get the closest length set available [color:"red"] btw, if your one of the people that still does not own an adjustable push rod! you can easily make your own by cutting a stock pushrod in 1/2 (2 pieces), removeing 1 inch from the total length an then with about 2 " of a 4 inch section of 3/16 or 1/4" thread rod installed and (in one section epoxy it in place leaving about 2" sticking out thread two nuts onto the thread rod and slip on the other end of the cut pushrod,(no epoxy) use the two nuts to adjust to stock length and let the epoxy harded in the one section[/color] now you can easily measure and order custom push rods useing the pushrod checker and adjustable push rod as tools AND YEAH IT ONLY WORKS WITH THE CYLINDER HEADS ON AND THE INTAKE REMOVED BECAUSE THE HOLE IN THE CYLINDER HEAD that GUIDEs THE PUSH ROD WON,T ALLOW THE NUTS ON THE ADJUSTABLE PUSHROD TO PASS THRU, UNLESS YOU PLACE THE CUT ABOUT 1" from the UPPER END OF THE ADJUSTABLE TEST PUSHROD [color:"red"] BUT I prefer to place the adjusting nuts centered as I like to watch for all clearances with the intake manifold removed while manually checking as I turn the engine over by hand durring assembly, and at that point, while checking all the clearances, I use test springs which apply very little load on the push rod[/color] http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=3272&prmenbr=361 HERES OTHER TOOLS YOU MIGHT NEED SOMETHING TO READ http://www.compcams.com/information/Products/Pushrods/ CCA-7705 5.800 in. to 9.800 in. adjustment range, Master pushrod length checker 4 piece kit ... $78.69 here Quote Link to comment Share on other sites More sharing options...
Corzette Posted March 2, 2003 Author Share Posted March 2, 2003 Thanks guys for all the help. I understand much better now. I ordered the CompCam adjustable for $25.00. Yes I did deck the block about 1 mm. I have the retrofit setup for a SBVC350 so it may be different. The damn lifters were different and cost me over $400 bucks! The rods are the last thing I need...I GOT MY CAR BACK TODAY!!!! Man am I stoked just to see it parked out back. I spent all day putting in the new door and window seals, the lights, mirrors, and fitting the roll bar...cant wait till next weekend...engine should be done by the end of this month.... Till next time! Quote Link to comment Share on other sites More sharing options...
Mike C Posted March 2, 2003 Share Posted March 2, 2003 The one Grumpy posted is the Proform tool. Manley has made it for at least twenty years. Quote Link to comment Share on other sites More sharing options...
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