Quote:
Originally Posted by Myself
Well, for starters he's got Edelbrock RPM heads with 64cc chambers! With that Eagle rotating assembly, that's OVER 10.5:1 compression! So, basically we have a VERY nice street strip smallblock with grandpas low compression smogger 350 RV cam in it! It's just wrong! It's like spending 75k building your dream garage and leaving a gravel floor in it......it's just wrong!
Change the cam AND intake, you will not know what to do with all the tire smoke!
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Thanks for taking the time to write this out. I definitely need another set of eyes on it!
Pat
Quote:
Originally Posted by SCOTI
I'd like to hear the theory as well.
Specs:
270/278
217/225 @ .050
.495/.500 w/1.5's
110LSA
That combo should offer plenty of cylinder pressure for low end grunt. I didn't do the math on the combo but can. I would also recommend a dyno session if possible. A 2nd set of eyes going over everything might not hurt as well. Sometimes someone else will see something differently.
*EDIT*
Quick calcs w/some guestimating:
4.030 bore; 3.75 stroke; 5.7" rod; flat-top/6cc valve reliefs; .039/4.10 bore head gasket; .025" deck clearance; 64cc heads
With a mild cam like that (34.5 IVC) & the combo mentioned; compression numbers 'suggest' around 10.4:1 static/9.18 Dynamic compression.
The heads should still work just fine. The intake while 'small' for a 3.75 stroke SBC would still work but it won't offer full top end potential. Below 3500rpm? It should be very close to the RPM series of intakes. Calcs suggest ~400hp/5krpm based on 250cfm intake flow @ .500 lift. So if that's achievable, there's something possibly not set-up correct.
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Thanks a bunch for your information. I too, feel there's power somewhere that I'm not able to achieve.
Pat
Quote:
Originally Posted by SkidmoreGarage
Why would spending more money on parts be the solution to the problem, that's just guessing. Engines aren't that complicated. If it feels slow (but without an actual measurement and assuming 300hp) it's probably down 100tq/100hp. Unless something is broken, you won't see that kind of power loss with just
non-ideal aftermarket parts. With an "RV cam", you should see more peak torque than HP. This should feel snappy and fast when you step on it, even if it has falls on its face once you get moving.
A dyno is probably $500, and will tell you a lot more than musical chairs with nice parts. It could also save you an engine rebuild, as a lot of power issues come with incorrect air fuel ratio. An old school guy may be able to tell you something similar with a drag strip, but that kind of expertise doesn't come cheap. With a good dyno tuner, you can also make some changes and run again.
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It definitely doesn't feel snappy. In fact it feels sluggish. Even though I have 410 gears, there's no way it would break the tires loose.
I think a dyno tuner is a good way to start. Thanks for the information!
Pat
Quote:
Originally Posted by Ziegelsteinfaust
Because it allows the individual cylinder to draw from both sides of the carb.
It evens out afr, and smooths out the carburetor signal.
Plus can reduce the needed size of a carb in many engines.
Provides extra plenum volume some combos really need with out a manifold change. A 1" spacer on a Super Victor manifold is not the same thing on a Performer dual plane manifold. Where the concept really shines by comparison.
Does it work on a dead stock low compression smogger 350. I have tried it, and got no where. This was a last tuning trick on a already well tuned engine.
This is a worse case scenario, but I have done it on a built 350 that I had for a sleeper build I was fascinated in. It had Dart iron eagle heads with about 190cc runners, and 64cc chambers. Followed up with 9.5-1 compression, and pretty wicked circle track mechanical flat tappet cam. I ported a cast iron intake to get as much advantage out of as possible. When I got it running I had the Q-jet on the manifold as normal, and it was pretty wicked. After hours of needle, and other changes.
Well a few weeks later I made a 1.5" spacer out of resin coated wood because of a article I read, and the truck was on the road fully as a back up vehicle. Plus I recovered financially, and emotionally from the project. So I had time to play again. Drivibility went up considerably, and felt power was across the board.
Its hard to say in words, but the cam/carb combo was not ideal. Just when driving the truck when the engine was up to temp it had a bunch of flat spots in part throttle. The spacer smoothed out idle, and removed all but one of the flat spots. That flat spot was at just under 2750rpm under full throttle. Plus I had to lean the carb out again due to more even air flow. So mpg would go up. It got crap mpg anyways so it would be hard to confirm, but memory says it went from 11mpg to 12 mpg. Under the more idealistic conditions, but not really noticeable bombing around town. That engine drank gas.
As for power before it could easily bark the tires hard in second. After it could continue the burn out into 2nd gear.
HotRod, and Carcraft have a bunch of articles on how they work. Plus they hopefully can explain it better then I could.
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Thanks Bud! I definitely don't need to worry about 2nd gear, as I can't even get the wheels to spin in 1st gear.
Pat
Quote:
Originally Posted by gmc684x4
Do you have stock style stamped rocker arms?
"I have three questions
(1) I have read that I might need longer push rods for these heads? Im putting them on a 350 with stock stamped rocker ar ...read more
Asked by ROBERT on January 23, 2018
A:
(1) YES, if you choose to use OE stock stamped steel rocker arms, you need +.100" longer than stock push rods # 9629
(2) YES, however you need at minimum Hardened Washers under the OE stock head bolts, and you should confirm length before bolting on your engine.
(3) YES, your early model Performer intake manifold will bolt directly on without issues.
NOW, why would you consider Angle Spark Plug Cylinder Heads? The Angle Spark Plugs may not clear your exhaust. Why will you use stock stamped steel rocker arms, and hope the slot in your rocker arms accommodate the lift of the camshaft you're using. Thank you for your inquiry...."
https://www.summitracing.com/parts/edl-60995 |
No, I have roller tipped rocker arms on the motor. The engine builder based the length of the push rods off of these rocker arms.
Thanks,
Pat