Will be installing a comp cams XE268 (as recomended) will this be compatible with standard push in studs? or do i need a screw in kit, max revs 6000, secondly not sure if a need different length pushrods due to following maching :-
heads machined .030"
block decked .014"
.015" shim gasket instead of GM .051"
third & finally would just 2 glasspacks (dynomax,summit part no wlk-24201) with "H" pipe be adquate silencing for street on 355 est hp 330, wish to order everthing at once from summit.

There are sure alotta SB's running around w/o screw in studs so your's are fine. Imho..

Just watch them every so often to see if any are pulling up.

And you can pin them with 1/8" x 1" roll pins b/c I ran pinned stock studs for years fine..

But if you do opt to go screw-in studs, remember that it is also a good time to go guideplates so you will need to machine down the stud bosses for them as well as drill out the heads pushrod guide slots or else there is a very good chance the p/r's will bind between the guideplates and the slots! pdq67

Back again, I forgot about the other two questions.

You are right at, by the numbers, .080" short so you might consider going with .100" shorter p/r's or else just checking them and ordering a set of custom length p/r's that will bring you dead-nuts to stock!

As for the glasspacks, I love the sounda them "Cop-calling" glasspacks so will say that they are loud but really so only when you put your foot into them... He, He!! I like the Walker/Dynomax/Thrush perforated core type b/c they flow the best!!

And they will be "quieter" with true long tailpipes to help get the sound as far from you as possible out the rear of the car..

pdq67

Cheers pdq 67 the push ins sound 'safe' enough, didnt want to throw to much money at current heads, will get decent aftermarket ones in time.
will order those dynomax glasspacks too at $16.95 a pop or $18.95 for the 2 1/2" ones it a steal yes they do exit right at back, system actually passes under rear axle (keeps pipes straight ! )

steady 78,

Years ago, I dropped a full house 409 in my car, I put three glasspacks per side on it and ran flexpipe under the axles like yoiu are talking about!

I used two, 2.5" x 24" or so old, can style Thrush with the adapter pipes cut off and welded together right off the exhaust pipes and then one, 2.0" x 12" generic bullit bodied glasspack as a resonator down both sides for a TRUE straight-through exhaust system!!

And my .060" over, 409 that was about 11.75 to 1 CR. back then sounded choppy/barky with a NASCAR solid cam in it!!

That's when I realized what a high CR. does for an exhaust note...

As silly as it sounds, the old style, big bore, short stroke, 409 ran a whole lot like a SB!!!! pdq67