ok so i bought the engine for the project

its a gen v bbc merc block
it has 7/16 push rods, can i go to 3/8" is there an advantage?
what cam/lifter kit?
stock heads, change springs?
what carb/intake setup

just looking for a little help to make 400hp or so? thanks

of course doing everything on a budget and engine is at the machine shop now

You can go 3/8" pushrods, but I think the answer would depend in whether or no you should...The only advantage IMO is less sprung weight on the smaller PR...You will need to change out the guide plates also...

7/16" PR's also IMO are more stable (not necissarily stronger) and I have used both, but think they are very comparible.

Not to convolute the thread, but where (what RPM) are you looking to get your 400 HP?....

The stock heads on that Merc should be small port junk unless it was an HO..

The springs need to be matched to the camshaft, as does seat pressure...

I guess all of the questions are for you...

You should ask yourself.

1-what RPM would you like to be at as far as WOT?

2-Headers, manifolds w/OT's, Thru hull?

3-BUDGET?   

4- what pump details can you share?

5-how will it be used??

You got homework my freind 

GT