Hi all.  Im starting to second guess my selection of intake manifolds, and I figured Id ask the experts to get some additional thoughts.

Car is a 56 Sunliner w/a 292, FOM, with blue thunder intake and (currently) an edelbrock 500 carb.  Dizzy is a '57 type w/pertronix.  Cam is from mummert - 224 duration at .050 lift for intake & exhaust, with 110 seperation.  (grind number is 270-3; bought it from mummert per his recommendation)

Issue that Ive been struggling with is a sloppy low end throttle response/lack of torque.  I know some of that is the cam, but after doing some reading, and based on some new tests, etc (i.e. Teds research/thoughts), Im starting to seriously wonder if Id be better off with a different intake?  Most opinions seem to be that the blue thunder makes less TQ than a B manifold below about 4k revs or so, if im reading info properly.  Problem is that with my FOM, my car hardly ever sees over 4k, even under WOT.  So Im wondering if Id increase around town driveability if I went to an OE "B" manifold?  I know that John M is working on a new Blue Thunder that is supposed to be better in the low end, but I havent seen/heard when that will be available....

Other question is if I should be running a bigger carb...with either manifold.  Also, if consensus is that a B manifold is better, what is a reasonable price to look for?  And woudl it have to be bored out for use with a holley or edelbrock carb?

Thanks to any and all for constructive thoughts and help!!!!

Ron Grove

Wauconda, IL

I have no experience with a blue thunder, but what you DON'T want with a 292 under 4000 rpm is a bigger carb.  Samller would help your driveability, even with the BT IMHO.

John - "The Hoosier Hurricane"

It sounds to me like for your use, you have a decent combination. I think I would play with the timing and advance mechanism to make sure all is well there. The Blue thunder is still a good choice for the setup, considering what it will cost to change it out. I had the same setup for awhile ( minus your cam choice) and all was improved over stock

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

Yeah, I have played with carbs and timing, etc.  I had a thread a while ago swapping a holley 390 & edelbrock 500 and tunign for driveability, etc.  Holley had marginally better throttle response, but did not pull nearly as hard at WOT, so I stuck with the edelbrock.  Have also messed with timing quite a bit.. Definately likes more timing than less...

Intake is kind of the last part of the equation that I havent experimented with until I saw diminishing returns, so Ive been doing some digging and figured Id ask the question.  Based on what Ive read, I cant help but think that a B manifold with the edelbrock wouldnt provide better low to mid range torque.  But I guess im not sure if it would be noticeable, etc....or if its all in my head.   I have a tendency to waaaaayyy over analyze things!

Ron Grove

Wauconda, IL

For your purposes a B maniflod would probably work better than what you have.Having said that I'll say that apparently John Mummert's new intake would be even better.My brother-in-law called John last week and was told that a run of  the new manifold will be available in about 3 weeks.

 

Paul,

Boonville,MO

zp cfjmoefwl

-Gary Burnette-

My computer is acting up???? Here goes again, Your combo may do better with a smaller carb ( 390 cfm ) and timing set at 12 degrees. Make sure the timing is advancing as the engine speed increases. even 14 degrees may work better if the engine does not ping under load. Ted chime in with your thoughts.

-Gary Burnette-

About your lack of low RPM torque and drivabilty issues I think you nailed it as a combination of heavy convertable, FOM transmission and a too big cam. Either change the cam or put in a lower rear gear ( higher numerical axle ratio). You are using manual low to get a first gear start are you not? Put a vacuum gage on it and tell us what you read in gear and stopped and what RPM.

?

at this point im not going to change the cam, and not looking to monkey with different rear gears.  Just not worth the headache, especially for a car that gets 3-4k miles/year.  Im looking for incremental improvements here, as it drives "ok" as is.  like most guys, just looking for a little more.... ha ha ha..

And yes, Im familiar with FOM weird 1st gear programming (now THAT would be a great mod/change!  Figure out how to get it to start in 1st EVERY time!!!!)

WHen I was messing with carbs over the summer, IIRC, vac was around 12.5 in gear at about 500 revs at idle.

Someday if I ever get around to either rebuilding this engine or putting together a higher performance oriented mill (better heads, higher CR, etc.) Ill use a different cam, etc.  And at that point Id consider a different trans, too....but that is all a looooonnnngggg way off, if ever.

Thanks!

Ron Grove

Wauconda, IL

Howdy; I think PWH42 is correct on using a ECZ-B intake. I was told they were for a 292 truck motor for more torque. And some times electronic ignition does not work as well as a 57 to 59 distributor with both vacuum and centrifugal advance. I have had very good luck with this combo on a 292 with 389 rear gears. It is reasonable to do also. Also would not go higher than a 550 cfm carb.