[stang351]

Hi I was wondering if anyone is running this combo?I am getting ready to drop the 351w in my cobra it has edelbrock #60379 heads,1.7RR and a F303 cam and my pistons are TRWL2446F30,whice are dished pistons.I was wondering if I will have any valve to piston clearence problems?I have the motor all together and spun it over by hand and everything feels fine.Also will the springs be o.k on the edelbrock performer heads?I heard they will be fine to a .575 lift.If I did my math right I am going to be at .544.I guess it is a little late in the game since the motor is together but I just thought about this.Thanks in advance for the help.Bill

 

[89 GTGHOST]

wow...f cam and 1.7's...thats pretty tight...too late to go to 1.6's?

 

[stang351]

I was wanting to try to stick with the 1.7's if at all possible.

 

[macx]

When you spun the motor over, I imagine your lifters collapsed all
the way against the valve springs? That would give you more clearance
than when the motor is running and the lifters pumped up.

The way that is often checked is to install light "checking" springs on
the valves for one cylinder so you can easily push the valves open by
hand, fix up an old lifter so it's got the equivalent of .060 preload on it
(collapsed .060 from when the plunger is at the top), then rotate the
motor slowly in the normal rotation direction and keep pushing
down on the valves every couple degrees of motor rotation when the
piston is near tdc. If you need to measure the actual clearance,
you can either push the valve down onto the piston and then measure
the clearance between the valve stem and rocker tip with a feeler
gauge to see how much you've got, or rig up a dial indicator on top
of the rocker tip and then push the rocker & valve down till it hits the
piston and that also will give you your actual clearance.

If you find you're too close, one thing you might try is to either
advance or retard your cam a couple degrees, might make enuf
difference if you're not far off, and a couple degrees usually
don't make THAT much of a difference in performance.

 

[128chris]

i had a similiar combo in my cobra with that cam and 1.7's and destroyed the valves. It ended up blowing my rockers off as well. I put about the same combination in the 89 i have now cept i have the 1.6s and is all good.

 

[stang351]

So what I am getting so far is pretty much to ditch the 1.7's and go with the 1.6's to be safe.I really do not want to chance it I know my pistons are dished but not sure if it is enough to give the clearance I need.That is probly what I will do,any one else with suggestions??

 

[stang351]

I am still undecided what to do.If I pull the heads back off of the motor will the heads gaskets still be good to reasemble?I was told by a friend they will be o.k since it has never been started.I plan to use clay and see what I end up with.