Reply With QuoteI will dyno both sets I just trying it to see if the power would be close @ useable rpms.
There Ya go.,That will answer your question better than any of us could.
Let us know how it turns out.
I was wondering if anyone had run 390s on there tunnel ram set up. I am putting together a bbc small roller 238/244 @ .050 comp cam,1.8 rockers,old 1984 weiand tunnel ram, dart 269cc. I was just thinking the small carbs might be better drivability than the to 750carbs I have. I will dyno both sets I just trying it to see if the power would be close @ useable rpms.
I will dyno both sets I just trying it to see if the power would be close @ useable rpms.
There Ya go.,That will answer your question better than any of us could.
Let us know how it turns out.
A couple of 600s would probably be a nice happy-medium. Other than that, Edelbrock has 500s available for more driveability.
390s might be a tad small for top end. Depends on what you are going to use it for/how much driveability you really want.
1.8 rockers, good lord! Did it just not have enough lift for you? Surely you could have found a cam with the lift/duration you want without having to stress the valvetrain like that.
There Ya go.,That will answer your question better than any of us could.
Let us know how it turns out.
I will definitely let you the results. I wanted to try it my train of thought was a 390 will make 500hp on a 23 degree iron head 350. Why wouldn't 2 easily support 600+ ? I just thought it was something out of the norm that could turn into some interesting stored useless knowledge.
A couple of 600s would probably be a nice happy-medium. Other than that, Edelbrock has 500s available for more driveability.
390s might be a tad small for top end. Depends on what you are going to use it for/how much driveability you really want.
1.8 rockers, good lord! Did it just not have enough lift for you? Surely you could have found a cam with the lift/duration you want without having to stress the valvetrain like that.
The carbs are what was at my disposal so that is why 390 / 750 route. I had 660s but they had sat for to many years to be resurrected.
As for 390s size being to small the old bush cars made more with one of these than I could hope to acieve with 2.
I guess I just don't understand your statement concerning stressing the valve train. I have 5/16 valves, psi valve springs, del west retainers, stud girdle all of which I was thinking was overkill for a bbc in a jet with a b stainless impeller.
I didn't think it would turn much over 6500 rpm,but that is why I was putting out feelers to see if I was way off in my combination. Even though it is a different approach than the usual combo.
I bought the comp cam and new crower lifters for 250.00 so that dictated the rockers I thought the cam was a little on the small side. And this helped free up money for the high tech stainless instead of the pro magnum.
Very true on the small carb thing. Heck, look at what some of the roundy-round guys get off of a 2-barrel!
Hey, run whatever rocker you want, it's your motor. It is just a rare occurrence to see 1.8s on a small block. With large ports and such these days, stud bosses get thinner and thinner. I was more thinking of the upwards pull on the rocker studs with that much leverage on top of them.
I am, however, curious as to the benefit of the 1.8s? I am not being sarcastic, just totally curious.
I must not have given enough info first time it is a 454 + .080. The dart heads heads seem to have a large stud boss. Plus the stud girdle should help stiff things up. I guess I am glad I brought this up if it should be an area of concern better to head it off now.
I must not have given enough info first time it is a 454 + .080. The dart heads heads seem to have a large stud boss. Plus the stud girdle should help stiff things up. I guess I am glad I brought this up if it should be an area of concern better to head it off now.
Nope. You gave enough info the first time. I SWORE I saw SBC at the beginning, so was thinking small-block this whole time. 1.8s are no biggie on BBC. Sorry, my error.
Back to carbs, with your 471-incher, 500's would be the minimum, I would think. Yes, some of the race motors make big hp with tiny carbs/restrictor plates, but those are also much smaller displacement. Yes, it can be done, but you are talking very high-tech cam profiles, porting, high compression, etc.
My "little" 346 cu in 1957 Ford Y-block (stroked 312) made 18 more hp going from a 500 edelbrock to a 625. The numbers will be exponentially more on a BBC.
My idea of the 390s would be fairly crisp throttle from idle-3500 or so and then it would run out of airflow. Just an idea thrown out there.
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