[uneasyrider]

I have a 461cid putting out 500hp and 562ftlbs. I’m looking for a new mechanical fuel pump for it. I can’t find the receipt for the old one so I don’t remember what brand it was and it worked great. It’s feeding an 850cfm Q-jet. Anyone have a suggestion on a good pump?

[1968GTO421]

I prefer the RobbMc fuel pumps. They are rebuildable. They come in two sizes, 550hp and 1100hp. The first link is the 550hp one , second link is the 1100hp one.

http://www.robbmcperformance.com/pro...ontiac550.html

http://www.robbmcperformance.com/pro...ntiac1100.html

Home for RobbMc---- http://www.robbmcperformance.com/products.html

[Jim Moshier]

I was thinking about running the RobbMc Gen 2 Powersurge so I can use the stock mechanical to supply the fuel and still be quiet.

[ta man]

I've seen my fair share of "dairy queen" cruisers with engines that should make 500 hp plus fall flat on their face at the 1/8th mile at the dragstrip. The usual cause is a mechanical pump.
I shake my head every time I see these threads. Guys will spend countless hours planning their builds...long cam discussions..trying to squeeze extra power out of their builds and then run a mechanical pump on a higher horsepower build. Doesn't make sense to me..running an engine lean isn't good.

[RocktimusPryme]

Originally Posted by ta man

I've seen my fair share of "dairy queen" cruisers with engines that should make 500 hp plus fall flat on their face at the 1/8th mile at the dragstrip.

Mine was about 100'. Its a Q jet though, a Holley with two bowls might have bought me more track.

I had the Robb 550. Fell on its face with street tires. Switched to the 1100 with a vapor return. That made it down the 1/8 on street tires. But when I put drag radials on it this year, the falling on its face returned. I may have been able to patch that issue if I had run the tank slap full.

At the end of the day I bought a Tanks inc LS swap tank used locally, converted my Robb MC regulator to return style, and the problems went away. At least in the 1/8th.


I think the fallacy is that its easy to feel like staying mechanical is cheaper. For me, and for others with similar experiences, I spent more time and money trying to get the big mechanical to work, than if I would have just gone with the in tank pump to begin with.

[TCSGTO]

Originally Posted by RocktimusPryme

Mine was about 100'. Its a Q jet though, a Holley with two bowls might have bought me more track.

I had the Robb 550. Fell on its face with street tires. Switched to the 1100 with a vapor return. That made it down the 1/8 on street tires. But when I put drag radials on it this year, the falling on its face returned. I may have been able to patch that issue if I had run the tank slap full.

At the end of the day I bought a Tanks inc LS swap tank used locally, converted my Robb MC regulator to return style, and the problems went away. At least in the 1/8th.


I think the fallacy is that its easy to feel like staying mechanical is cheaper. For me, and for others with similar experiences, I spent more time and money trying to get the big mechanical to work, than if I would have just gone with the in tank pump to begin with.

What lph rating pump and what size feed/reed and return lines are you guys With the intank pumps using?

[RocktimusPryme]

Originally Posted by TCSGTO

What lph rating pump and what size feed/reed and return lines are you guys With the intank pumps using?

Mine is the tanks inc GPA 6, 400 lph. Which is waaaaay overkill for a carb. But as I mentioned, I bought mine used from a guy who had an LS swap.

Im using -8 to a 1/2 stainless feed line, and -8 return all the way back. The regulator is the same Robb Mc regulator I was using when I was mechanical, but it was converted over to a return style.

[RocktimusPryme]

If you are dead set on mechanical I will second Robb Mc. If you are going to do any racing I would go straight to electric. I’m sure it’s beating a dead horse, but it’s so much less of a headache.

[TCSGTO]

The RobbMc 1100 is the highest flowing mechanical pump at higher output pressures made for a Pontiac bar none.

[AG]

My brother's car makes 530 Hp and uses a Carter 120 GPH mechanical pump with no fuel starvation issues.

[78w72]

Originally Posted by AG

My brother's car makes 530 Hp and uses a Carter 120 GPH mechanical pump with no fuel starvation issues.

does he run the car at the track? what are the times? im about the same HP level & doing low 11's & the carter/edelbrock type pumps definitely had starvation issues at those times with a q-jet carb.

[AG]

Originally Posted by 78w72

does he run the car at the track? what are the times? im about the same HP level & doing low 11's & the carter/edelbrock type pumps definitely had starvation issues at those times with a q-jet carb.

No track runs just WOT through the gears on the street with an AFR meter.

[ta man]

Originally Posted by AG

No track runs just WOT through the gears on the street with an AFR meter.

Big difference in the amount of G force...

[uneasyrider]

Originally Posted by 78w72

does he run the car at the track? what are the times? im about the same HP level & doing low 11's & the carter/edelbrock type pumps definitely had starvation issues at those times with a q-jet carb.

Thanks, it’s a street car. I found my receipt and it was a RobbMc I had on there. It worked great! 😎👍

[tom s]

I use the Carter street pump with no issue.Tom

[uneasyrider]

That’s why I will never leave this site, always get a good answer and usually promptly. Thanks guys! 👍

[78w72]

Originally Posted by tom s

I use the Carter street pump with no issue.Tom

on the street?

the carter/edelbrock pumps will be ok on the street at ~500hp, its when you get to teh track with good traction & get into the 11's that the issues can happen.

[Formulajones]

I haven't had huge success with mechanical pumps when approaching the 500hp mark.

Using bone stock pumps and fuel lines, I've gone mid 12's at 108-ish mph with a completely stock fuel system and ~400hp. But as the car makes more power it's not enough.

Using either a holley aftermarket mechanical pump or a RobbMC would get you by at 500 HP on the street but I wouldn't expect stellar performance at the track. I've done the Holley pumps and they are "okay". Friends have used RobbMC mechanical pumps to 11.30's at 116+ mph with bigger 1/2" lines but report low fuel pressure at the end of the track (less than 3 lbs.) Not ideal.

As mentioned, if racing in mind, even just once or twice a year, I'd recommend an in tank electric setup, even on a street cruiser. OEM reliability and excellent fuel supply under all conditions.

I recently went through 3 Carter stock replacement mechanical pumps before I finally got a good one that ran the car more than 3 miles from the house before it died on one of the vehicles here LOL So I'm liking the mechanical pumps less and less for reliability reasons these days, let alone WOT fuel supply. If I'm going to run one, it's definitely going to be a rebuildable unit, with a spare kit in the trunk

[tom s]

Is this not the street section?Tom

[RocktimusPryme]

Originally Posted by tom s

Is this not the street section?Tom

It is, but this isn't really like running a big snotty cam that could have some detriment on the street. An in tank fuel pump is going to be better on any kind of track obviously, but is as good if not better on the street too.

I wouldn't say my car is a race car, but it finds its way to the track a few times a year. Not very fun falling flat on your face.