I've been doing lots of research and reading up here, and am still in need of some advice. I'm gearing up to pull my motor in order to swap k-frames, and want to correct a few things from my last build while it's out.

I need advice on...
Cam: I over cammed on the original build, and need to pick out a new bump stick. I'm thinking along the lines of the ComCams 252 or Doc's RV15. Reasonable performance, decent street manners, and good fuel economy are what I'm after.

Carb: Currently have a scrounged together 350cfm Holley 2300 on a super six intake. However, I just picked up an Offy 4bbl intake, so that expands my playing field if need be.

Helpful details...
Motor:
'76 225
engnbldr valves, springs, etc.
Minor unshrouding work done, and gasket matched ports.
Head and block shaved for ~9.1:1 (I can't find my build notes at the moment)
.030 over
Rotating assembly balanced
Hughes double roller timing chain
Dual dutra duals, y-ed into 2.5" to muffler, 2.25" tailpipe

Car:
'76 Dart Swinger
833od
8.75 / 3.23sg
25" tall tire

Purpose:
Daily driver/corner carver, but sees 5+ hour freeway trips regularly. Fuel economy is definitely a strong consideration.

Need pointers on a cam and carb to play well with the rest of the build. Thanks for the continued schooling, gang.

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a Comp 252 and 9:1 sounds like detonation to me.

What cam have you now?

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Yeah....Im the one who destroyed this rare, vintage automobile.....

280/270 RDP regrind from Delta cam.

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No that works, that was my original build for my super six setup in the feather duster and worked well for the 390 cfm holley on the hyperpak intake with the dutra duals and 3.55's in the rear.

My build for that was:

9.2:1 compression, .020 over, had to scrape .110 -.090 off the deck and .020 out of the head for an original 1976 forged crank block and head.
Standard valves and springs, mild porting/gasket match
Comp Cam 252 installed 4 degrees advanced.

Once I sorted out the timing it liked 50-52 degrees on highway using regular and got up to 26 mpg (hot lean days in summer), 24 highway average. 54 degrees of total on highway did not give anymore benefit.
Lots of torque across all the bands (never found the top end of this build as there wasn't enough road to handle the last 1000 rpm on the clock-I was already booking at 125 mph calculated-the speedo stopped registering after 100 on the 120 stock speedo).

Engine lasted 50K of daily abuse and hyperpak road testing. The engine now sits on a stand in my shop waiting for a day in case I need the matching engine to the Feather Duster Again.

I think getting the RV15 would be a bit better since Comp's QA/QC hasn't been so great in the past.

-D.Idiot

That's what I've been reading. My v8 buddies like them, and suggested it, that's all. I'm not set on either of those, just from my limited knowledge they seemed like close to what I think I need? The specs I have on the RV15 show a 106 or 108 centerline, while most of my reading has me thinking a 110 is ideal. Does that hold true for slants, too?

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tighter lobe centers = more torque...but wider lobe centers to a certain point = better idle depending on the grind in question... 108 is fine, 110 = better idle...the caveat to this is that the wider centers also decrease/shorten the overlap event which can have an effect on not allowing the cylinder to bleed down pressure during the "scavenging" event...this doesn't work too good with a high compression engine using a short cam, as typically the cylinder pressure will rise and you get lots of ping/detonation (looks really impressive on a dyno program though...LOL). Since you are in the 9:1 range the short cam is fine and even the RV15 with a 108-110 would work either way...worst case scenario go 109 splitting the difference i don't think you'd notice much there.

-D.Idiot

225s like less lobe separation angle and more cam advance (centerline) than almost any engine out there. I would use LSA = 108 for a mild NA engine like yours, and 105-106 on racier cams.

Lou

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