Ram Air IV versus 455 HO

[Charley Lillard]

So I can use the comp XE274H and some Ross 10-1 Pistons, have no valve to piston clearance worries ? Yes this is a 73 SD that is bone stock.

[Steve_Hoog]

You will have no problems with clearance, Ross will take very good care of you. I would suggest using 1.6 full rollers. Jim Butler is great to do business with, if you need a reference.

[Chevy454]

Ross, JE, or CP pistons...can't go wrong with any of them. I went with CP's in our last L-72, and they were BEATIFUL. I *believe* they're a tad lighter as well. I'd use them again in a heartbeat...

[supergonzo]

Charley speaking of references: I can vouch for the Butlers,I personally speak to Rodney/Jim/David almost daily about Pontiac set up tricks and applications. I also like Paul Spotts, He's a good guy and I can help you with him as well. Email me if you are thinking of using any Pontiac guys to do any of your work.

[Charley Lillard]

My engine parts are at my machinists right now. They are also recommending a hyd roller cam so I guess before I commit to a roller I need to know that I don't have to modify the lifter valley at all. And what Comp Cams hyd roller. This SD block has all that extra webbing around the lifter bores so I don't want any suprises.

[supergonzo]

"I would recommend a Hyd roller possibly a Comp XR276HR or a XR288HR "
The 276 would idle just fine. The 288 will be a little lumpy, with about 14 inches of idle vacuum. But will give you more upstairs. If you are looking to just drive the car without ANY headaches the XR276HR would be fine. You do not need to modify the lifter gallery. But you MUST buy the whole Comp Cams kit including pushrods for you to not run into any geometry problems. 1.65 roller rockers would be great with this setup.
I had this exact Camshaft in a 400 RAIV car, and it idles fine, and runs 12.50's (with headers & stock quiet mufflers) all day long.
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On a previous note: The RAII heads were not exactly the same as RAIV heads with a different camshaft rocker arm ratio. The RAII heads had the same intake openings as d-port heads, much smaller then RAIV intake openings. However because of this extra casting they can be ported today very well.

[Charley Lillard]

Can I just run the stock rockers ?