Ram Air IV versus 455 HO - Page 5

Astock · #41 02-27-2004, 06:50 PM

I have 100% orig. '65 GTO 389-6 at Glasgo's getting the Phase III blueprint that will put the car in the 12's with the skinnies and full exhaust. And,they swear by the Comp cam XE274H.

Steve_Hoog · #42 02-27-2004, 06:59 PM

If you can not run your best time with full exhaust these days, you best put it back on the trailer. These younger kids racing today have corrected my way of thinking. Don't get me wrong, I still love the sound of open headers but when they run down the track in a full exhausted 9 second car.... I have to rethink things.

Dude, I love that repo Magnum the Glasco's built. Very very nice. I would think any work they do for you will be top notch.

supergonzo · #43 02-27-2004, 07:02 PM

Yes I like that cam as well. 230/236 degrees duration and .488/.491 lift with stock 1.5 rockers. A good street cam. Especially for a 389/400.
The 455 SD can take a slight step up in camshaft without affecting idle quality noticeably.(particularily lift) But that one is ok.

**Charley Lillard** · #44 02-27-2004, 07:06 PM

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 · #45 02-27-2004, 07:15 PM

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 · #46 02-27-2004, 08:00 PM

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 · #47 02-27-2004, 08:51 PM

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** · #48 02-27-2004, 08:56 PM

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 · #49 02-27-2004, 09:23 PM

"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** · #50 02-27-2004, 09:27 PM

Can I just run the stock rockers ?