Simple question. I have heads that were to an 86 Pickup. That I really do not want to use. But they were used with the roller cam, so they have the shorter rods.
I want to use my 73 heads, but it was geared towards the Cast cam and lifters with the long rods.

On my new build, Can i just use the short rods with the 73 heads? Toqure them down as normal?

Thanks

 

Every time I build an engine, I always check piston to cylinder head and piston to valve clearances (you can use an old head gasket to prevent any damage and it takes up for the new gasket flattening).

Just so I can make sure I'm understanding you here: you have a 1986 302 with a roller cam and you want to use the 1973 heads?
I think this has been done before. I don't know that your compression ratio would be.

 

You can't just slap pushrods in and hope it works. You need to get yourself an adjustable pushrod length checker. Comp Cams has a nice one that sells at summit for like $20. As long as you've got the right pushrods, there's no harm in putting your old heads on the new motor.

I would recommend, however, port-matching the exhaust on whatever set of heads you decide to use. SBF exhaust port castings are absolutely horrible. For a couple hours of work, you can have exhaust ports that flow halfway decent.

 

+1. You need to check pushrod length or you are only guessing. Guessing is not good when building a valve train.

 

Could I ask what is the normal workflow when installing the pushrods. I remember on the 68 all I had to do was place the push rods in and then torque down the rocker arms.

 

It depends on whether the heads have pedestal mount rockers (not adjustable) or stud mount rockers (valve lash adjustable) and what type of lifter you are running (hydraulic roller or solid roller).

 

I have stud mount rockers on the heads and the lifters are hydraulic rollers.

 

First you run the engine until it reach operating temp. Then, basically you bring each piston to TDC and adjust the rocker until there is no lash between the rocker and valve. You then tighten the rocker nut about 1/2 turn more to set the preload for the hydraulic lifter. You do this for each piston on the intake and exhaust side. Make sure you are at TDC and/or both valves are closed.

Another way is to adjust the lifter with the motor running and tighten until they do not make noise. This is very messy!

 

Sweet. That bottom way sounds like the way I was taught on the 68 setup.
Thank you for the explaination.

 

you'd be using the longer pushrods. the shorter ones are for use with the roller lifters, and the heads your using shouldn't effect that. of course, you always want to make sure your geometry is right when you slap those rockers on.

also, if i remember correctly i don't think the 73 heads are going to be any better and they *may* not have hardened ex seats in them.