I was ordering the gaskets we decided apon and the store owner hit me with this...
Also, fel #1256 intake has an open exhaust cross over.
Are you using an afternarket , alum intake?
If so use #1205.

Any thoughts..
Thank you

The 1256 will better match the heads and the intake. The IK180s don't have the crossover hole in the heads drilled, so it doesn't matter one way or the other. If the 1205s cost less, they'll work. If they're the same price, I'd do the 1256s.

ok Thanks BadSS, getting the 1256 set. gaskets have been ordered and should arrive in a week. hopefully make some time to get back to tearing out the 305.

My buddy says he has a non-ccc Q-jet and Distributor, good to know if I decide to try that way. I'm sure all these new parts will work either way I decide.

Also I was watching a uncle tony garage video on engine break in, he stated if your heads have heavy springs ,they should be
replaced with stock ones during break in, do you think that is necessary with my head choices?

Your springs aren't what I'd consider heavy, but it might not be a bad idea to break it in using the stock rocker arms. I've used the stock rocker arms for cams with lifts as high as 0.470" without issue. Yours would be .477" lift with the stock rockers, so you would need to make sure the slot wasn't contacting the stud at full lift.

Below shows the additional clearance that the aftermarket long slot rockers (like the 1.6s you bought) will typically have over a stock rocker arm. I think the picture and measurements are for a big block, but it gives you an idea of the area you need to double check with the stock rockers.



If this was 1990, I'd say just install the 1.6 rockers and let her rip. Now, I might tend to break it in on the stock rockers. Brent posted a video on what to check on the lifters and cam before you install them. That is VERY important to check.