73C3

I am in the process of doing a Vortec head/intake swap and cam swap on my 73. The motor is not original but I coded it to a 73 C-10 pickup.

Anyway, I am installing a Comp Cams XR-270HR with Comp Cams 853-16 retro fit roller lifters. The Heads are from Scoggins Dickey modified for 0.575 lift hydraulic roller cam.

My question is since I am doing a Vortec head swap and change out to a retro roller lifter system can I use my same push rods? Scoggins says original pushrods are good for the Vortec swap. I deceided to go with a roller cam afterwards and am concerned that the retro rollers will require a shorter push rod.

I need an expert opinion please.

Durango_Boy

The problem is that no one will be able to answer this unless they themselves have the exact same setup using the same parts.

The push rod length can only be measured after you have all components installed. You'll have to use an adjustable push rod to check for the length, and you can either buy one from a Jegs or Summit or borrow one from a local machine shop.

I went through all of this with my 405 that has aluminum Vortec heads, a roller cam with V6 roller lifters, and roller rockers. Stock won't work for me, and I must use an adjustable push rod to check the exact length and then order the new rods.

73C3

Thanks DB.

I have been doing some reading since the original post and it looks like the retro roller lifters require approx. a .500 shorter pushrod and total pushrod length can vary due to deck hight, gasket thickness etc. and unless the engine is bone stock pushrod length must be checked.

I will get a length checker.

SpE3dF0x

"Mr. 73C3," need to know that bit of info as well, I plan on doing this set up myself...thanks!

73C3

ok, I'll let you know how it goes.

Kind of a bummer though I was wanting to fire it up this weekend and shred some rubber. Unless I can get the parts locally that's not going to happen.

Durango_Boy

I borrowed an adjustable push rod from a local machine shop, and they sell many lengths of rods there. It's possible you could get it measured and get the proper length and still meet your weekend goal.

billla

CompCams makes a really nice pushrod checker where you read the length right off the tool vs. measuring with a vernier caliper.

Just a reminder that you need self-aligning rockers with the Vortecs.

Durango_Boy

...or...guide plates, hardened push rods, and non-self-aligning rockers.

OMF

Hi there, I did this exact swap with my 406. I used a different comp cam (XR276HR), the same lifters as you, and some comp 1318-16 1.6 selfguided pro magnum rollers. I had used the comp 7809-16 push rods which are 1/2" shorter. Once this was done my rocker contact pattern on the valve was perfect. You should get the pushrod checker though, because if you block has been decked or your using a real thin or a much thicker head gasket you may have to go .050" one way or the other on your rod length.

73C3

sstocker31,
I looked at the 7809-16's yesterday per you're advice and ordered them. They are about .504 shorter then stock which makes sense since the retro rollers are about .500 taller then flat tappet lifters.

They will be arriving today and tomorrow if all goes well I should know if they work for me. My deck is as far as I know standard and I am using just plain stamped steel self aligning rockers for now which are more forgiving.

Thanks for the advice

63mako

Always figure your pushrod length with an adjustable pushrod not mathematically. Too many variables. I bought the Comp cams kit with all their components and gave them the model number of the AFR heads and deck height of the block. The pushrods were still wrong. Check it and figure the exact correct length you need after everything is assembled.