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Discussion Starter · #1 ·
My old engine combo is below, I was originally going to go with an XE274HR and RPM heads but decided to go a different route. I posted pics of my shortblock a while back, heads will be here next week. this is what I got, tell me how you think she'll do.

306 roller
stock recond rods
polished crank
ARP everything
speedpro pistons
Moroso windage tray
Centerforce DF clutch
Summit SFI balancer
FRPP BS flywheel
Lakewood scattershield
Stef's fabricated oil pan
Cloyes timing set
Holley mechanical 110 pump
AFR 185 heads
Jay Allen Custom cam 218/224 ~.540/.550 114LSA
Performer RPM Intake
Biggs 650 DP Carb
1 5/8 longtubes
2 1/2" exhaust
T5z trans
9" locker with 4.30's
31 spline mosers
running 26x10.5 e.t. streets

Tell me what you think, how much faster will I go. I'll post pics before I drop her in.
 

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Discussion Starter · #3 ·
AFR 185's
 

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Are you interested in selling the XE274HR?
 

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Thats a really big cam, with those heads & gears I'd think it'll work really good too. Only thing I'd try is a single plane intake instead of that dual plane.
 

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I like the combo... except the intake could use an upgrade IMO. That is a big cam and great heads.
Should be a screamer!
 

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Big Cam? Where? Am I missing something in the cam specs or an I just used to looking a Racing cams? That cam would work great with a Performer RPM.
 

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the cam is smaller than the one that I use in my 302. I use an rpm manifold and it works great. Your cobo looks good to me.
 

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For a street car thats a big cam. Just from experience, the stealth or air-gap is better suited for that combo IMO.
 

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If thats a big street cam, how can you justify the 185's aren't they way to big for a 302 street car?
 

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Thats kinda my point... big cam, big heads... kinda needs a big intake to take advantage of them.
 

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Thats not really that big of a cam for a 306. The cam I run in my AFR headed 306 is a 264* @ .050 .575 lift. I cannot see the issue with the combo. The heads will pull a little more performance from the cam and the intake will ensure good low end performance. If he was to run a single plane intake the low end would suffer. I say for a street engine I would leave it alone.
 

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Discussion Starter · #13 ·
The first thing I thought when Jay got back to me with the specs that the duration @.050 was pretty low.

However, after reading some of Jay's posts over on corral.net, there is a lot more to cam selection than just .050 numbers. The duration @.050 doesn't mean that much, it's the valve timing itself that matters.

Generally, big cams bleed off cylinder pressure, and cylinder pressure is directly related to power. Since my compression ratio is only 9.2:1, making power is then a result of how effectively I can build pressure throughout the rpm range. This cam should make peak power ~6000, have a smooth idle and make the torque down low as well.

The general rule is that the better flowing the heads, the less cam you need to make equivalent power.
 

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I would agree with your statement, when you utilize the larger heads the cam can be made smaller and act different. But the cam still is relitively small
 

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Less cam may be a little misleading. Jay seems to like less duration while increasing lift with good flowing heads and induction. Not just throwing in a smaller cam.

The cam will act very small/streetable and be a beast when you put it to the floor with the small .050 duration and high lift. The only "big" thing about the cam is the lift. Even the lsa is very tame.

You're gonna have to get the carb dialed in.

I think it's a very good combo. I'm sure you'll be happy even with the low comp.

<font size=-1>[ This Message was edited by: 289nate on 4/21/06 4:44am ]</font>
 

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Discussion Starter · #16 ·
Yes, I expect that I will have to jet up. I plan to call Jesse Bigs and see what he says. He set the carb up for the 289 and it's worked great.
 
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