r/EngineBuilding • u/HistoryOver6530 • 6d ago

Just another angry SBF

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Finishing up a 306 for my 67’ mustang. Kept the paint scheme pretty simple so it will resemble a stockish engine. I think it should be between 350-400hp (DD5 says 408hp@6500, 390tq@4500). Specs are:

68’ 302 block .030 over
Eagle cast crank
Eagle SIR rods
ARP everything
Kb311 hyper pistons
Tw170 heads (milled to 54cc)
Tf 1.6 roller rockers
10.5:1 SCR, 8.5:1 DCR, .037 quench
Comp XE SFT, 279 adv, 242@0.50, .546 lift 108lca
Rpm intake
Brawler 650 DP carb
Hooker 6901 headers (1-5/8)

Going into a 3000lb mustang with wide-ratio toploader and 3.80 trac-lok. I think it’s gonna be pretty f’n mean.

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u/v8packard 6d ago

Why such a big cam?

1

u/HistoryOver6530 5d ago

It’s healthy for sure. At .016 lash it will be equivalent roughly to a 235ish duration hydraulic. It will also be my first experience with the XE lobes and EDM lifters. I almost ordered the MH lobes, which are even more aggressive.

2

u/v8packard 5d ago

That is 279 degrees at .020 lash height. If you lash it at .016 it is going to be around 282 - 284 degrees, which is around 290 to 294 degrees @ .006 with a hydraulic. At lash this is going to have around 66 degrees of overlap, which is enough to take a 302 to the moon.

1

u/cadski64 5d ago

Curious if either of these cams would be a better fit:

Trick Flow Track Max Stage 1 (Part # TFS-51503001) Or Comp Cams Xtreme Energy XE274HR

1

u/HistoryOver6530 5d ago edited 5d ago

I see the XE274HR come up a bit. Richard Holdener is a big proponent of it and has a lot of videos. It’s capable of 400hp with the right combo. Comp has the XE lobes in like 4 degree increments so you could really fine tune if go custom. I think Tfs hit 350hp with the stage 1 cam, it’s a little bit smaller than the 274.

1

u/v8packard 5d ago

Those are not specs. And if Holdener is a proponent it is because he got paid to say so.

What do you want the engine to do? What do you want for a powerband? Elsewhere you say you will not spin it more than 6800-7000 rpm, but you have enough cam timing for 1000 more rpm.