Just installed rhoads lifters.schnieder cam 236@050 and 510 lift,ported holley heads 750 mighty demon,3"exhaust.timing at 38 have moved to 32 no real differance except car starts faster and is much snappier on bottom end with more timing. Has a victor jr.and 3:36's.

i had the same problem once. turned out to be a bad fuel pump. might want to look into that. would just stop at 6k with a mechanical pump. went to a electric pump with better flow and would rev to 7,500 with no problems.

its the BG carb :D check fuel pressure,are the secondaries opening?

Check for kinks or other restrictions (plugged filter?) in the fuel system.

ok i have that same cam in my 63 nova it must have 373/390 gears i ran it with 323 and 6 grand was all i would pull. what gears do you have ? rhodes lifters bad choice for such a small duration. call rhodes they recomend at least a 252 duration . them lifters are breakin your cam down to like 218/222 duration. the bg carb is a waste toss that . as for a mechanical pump try a 140 gph at 7-8-9 psi and a converter of 2800/3200 a 1.5 intake rocker a 1.6 exhaust . is this your first engine build or dont you understand the basics of cmas gears and valvetrain/. :confused:

1.6 on the intake and 1.5 on the exhaust will, in most cases, make more power.

not to be disrespectful but i have to ask . its in my nature to do so. what on earth ever possesed you to install rhodes lifters on such a small cam? graemlins/clonk.gif

Originally posted by Rapid Robert:
its the BG carb :D I realize that was a joke, but for whatever reason, my Mighty Demon 750 was around a 6300 RPM rev limiter on my car and another car we tried it on.

We rebuilt it, had a reputable place go through it, and the only step left is to send it back to BG for evaluation. There was plenty of fuel pressure, volume, and the A/F was great on the dyno. Bolting on an old crusty Holley 750 cured the problem. I'm back to Holleys after that.

This was the first motor I built. I'm lucky it even runs. I don't know much about cams & gears just trying to have fun.

My combo mellows out at 5500 rpm. If I open the exhaust cutout, It swings to 6500 NO problemo. Got exhaust restriction?

the bg carb is a waste toss that
shoebox,have you had problems with your bg???
if so what i'd like to compare notes
graemlins/clonk.gif
shane

Ok guys, let's give him some credit for having the cahones to build a motor himself and that it actually runs. Seriously. :cool:

Anyway, I have no experiences with BG carbs, but if you have a buddy with a Holley, you might see if you can get together and swap carbs for the weekend. Wouldn't really cost anything and would either rule out the carb or discover the problem.

Get a fuel pressure gauge and verify that you have adequate pressure. Not actually sure if that would rule out inadequate fuel VOLUME, but maybe some else can verify that.

Can't tell you much about the Rhoads lifters, except they need to be used under specific conditions or there could be performance and driveability issues. Others will know more about them than me.

Valvesprings? Did you use the correct ones for that cam? Were the heads set up properly with all the right clearances, etc.?

What size rear tires are you using? 3.36's with a Victor Jr. single plane intake is not a great matchup. Especially if you are using a 28"+ tire. Probably not that great even if the tires are shorter than that. A single plane intake needs rpms. Tall gears don't provide that.

What transmission? What size headers? How much compression ratio? What size stall converter (if you have an auto tranny that is)?

Who did the port job on the Holley heads? If they've been excessively hogged out, you've lost velocity. That would be more of a loss on torque, but I can imagine a very poor port job might cost power all thru the powerband.

Lots of variables. Just be honest with what you've got and we can help you figure out the problem. Welcome to TC. You'll find many, many knowledgeable folks on here. smile.gif

Well i hate to tell you boys this but it isnt the carb thats causing you not to pull....my 750 mighty demon on my 350 lets me go as high as i want...hell i bet i could pull 10,000 with that carb. Ive gone a stich over 8,000 before and it just keeps truckin', although i dont need to wind it like that to pull maximum ET. The point is BG carbs are an excellent piece...it just seems all the holley boys get so offended by demon carbs. heck they are an equal/much better carb for less money. Get over it.

Now what heads are you running? What kind of ignition? Please get specific.

I realize BG carbs are much better than they used to be as far as being more "tuneable" but the old BG carbs had plenty of problems,is he running one of the older carbs? I'm not offended,more power to those that get em right,it was much easier to open the box,set the floats,mixture,idle and go,,,gotta love the HP950 :D

yes lets give him credit. i highly doubt this is his first motor from reading his other posts he seems fairly knowledgeable and i wasnt trying to make a fool of bb 485. yes i had problems with bg carbs junk pos all the way wouldnt pull past 6 grand at most holly,s the way to go for fuel delivery unless you have money to burn the fuel injection is nice.. bb485 try gears if u have none already and switch carbs if you can first . do the easy stuff before you waste money.. just trying to be helpful.. the rhodes lifters are nice but even rhodes says 252 duration max.. i have the same cam and i hit 11.80 in the 1/4 . and i hope you are having fun..

Thanx for some responses guys... Here is some info i pulled up.

Fuel pressure is good (6psi) in 2nd gear pulling a load.
The heads are Holley Systamax 2 (ported by Larry's track Pro).ValveSprings are old but correct for this application.
Turbo 400 w/2400 stall.
Headman headers and 1.58"
Comp 9000 ignition.
10.5:1 compression ratio
3:36 gears w/ 26" tires.

Victor Jr. intake w/ the lazy gears is not a ideal combo, however the car pulls good from a roll and cruize speeds. It almost seems like it has got adual plane intake. I think the rhoads lifters take something of the top and give it some more on the bottom end, b/c this combination drives around really smooth. I think the cam with such small duration(236 @ 50) could be limiting my rpm range to 6000.

I think you may be on track there

Originally posted by 11secshoebox:
not to be disrespectful but i have to ask . its in my nature to do so. what on earth ever possesed you to install rhodes lifters on such a small cam? graemlins/clonk.gif I've used Rhoads lifters on smaller cams than that. They really don't affect the upper rpm ranges that much, but they sure do make the low end smooth.

by smooth do you mean better bottom end power or just tame idle?

Hi Mike, did you get you intake or block cut or did you use the .125 gaskets?

Mike is correct & that is exactly what the lifters do.

And Congratulations on your "first" engine graemlins/thumbsup.gif

Gotta love the Holley / BG deal :D
The BG carbs are not a "POS"
While you can get a bad carb from anyone, this does not make the whole line bad.

While my preference is the HP series Holley's I have used a lot of Demons & have never had a problem with them if you follow their advice size wise within reason.
I have done two blown engines recently with Demons, Here's one:
http://wsm.ezsitedesigner.com/share/scrapbook/19/190264/392_Hemi_007.jpg

The carbs basically came out of the box & went on the engine with no problems what so ever.
I didn't even need to rejet the above engine.

I am doing another 400sb right now with two 650 Demon blower carbs that come boost referenced so you don't have to mess with them.

BTW, I disassembled all of these BG's & there was NOTHING inside that didn't belong like chips, filings,,, someone's contact lens etc. :D

As far as RPM limited??? How does a carb that is not too small limit RPM if it is opening all the way & getting enough fuel???
Unless it is going dead rich or lean which is highly unlikely.

One may make more power than the other which is what I have found in back to back testing of an old ugly 750 Holley I keep around as a "test standard" vs an EDE of the same CFM rating & the Holley made more power in both cases but RPM limiting???

Don't know, maybe I been lucky but I have just not found all these "problems" I keep hearing about regarding BG carbs ;)

My personal opinion is they are both an excellent carb the majority of the time.

Now,,, on the Rhoads lifters.
While I am not a particular fan of them, there is nothing wrong with using them on a cam of 236 degrees duration. The original Rhoads cam & lifter kit had a cam that was around 220 @ .050 as I recall.
You do not need them & I feel you would probably run a little better with a good set of "anti pump up" lifters but they are not going to make your 236 cam into a 218 cam above about 3000 or so.
I have used Rhoads in vacuum rule classes with pretty fair results to about 6500 with good springs.
I don't like them on the street & personally feel they are a band-aid for too much cam but they will tame a larger cam AT LOW RPM
At higher RPM they tend to act just like any other lifter.
They will also react differently with different types of oil. IE: 10/30 vs 20/50 & at different temperatures.

And on the rocker deal, in almost every case that I have tested 1.5 intake & 1.6 rockers is backwards & lost power as Pat mentioned earlier ;)