Hey guys I think I might have a problem big or small to be determined I swapped over from a cast iron boat anchor 2bbl to a Edelbrock RPM 4bbl .

I seen a brand new 😳 600 cfm street warrior on offer up for 200 the guy took 150 I thought I scored it's the early version almost a classic Holly basically , I had to buy the Ford kickdown bracket no big although my first problem occured with very lean acceleration . I did the common up 2 sizes but them I looked at the squirter it was a #25 ???? When I would take off it would be go really lean in he 16"s on the AFR till the 7.5 PV opens I had good WOT at 1160-1200 I also changed the rear plate to a block and I think there 86 jets in the rear now .

I put a proper 31 squirter and a high flow screw and it helped although it still went high on light acceleration and with a 67 main jet it actually popped out of the carb ? So now I'm coming up with stuff to richen it up .

I put a #35 squirter to fatten it up to stop the stumbles and cough 😷 It worked and I put a 9.5 PV so it won't go lean on me when I accelerate .
it runs ok my AFR right by off idle goes to 14 then the big squirt takes over and keeps it around 1290 light throttle cruise I'm good at 1380 14 AFR .

The main metering block looks like it's been mickey or defective I only have 1 brass incerts on the left none on the right and the holes are big there way bigger than 0.06 not sure how big does this look right ? I'm thinking this is were my acceleration problems are going lean and why I had to richen it so much I left the stock # on the block thanks .




I'm in thought that someone F up on a mod and then sold it cheap

 

No Holly carb Pros on here anymore ?
well just in case I can help anyone else on here I made a long post only to add every detail in but I eventually settled on a #35 squirter and a 67 main jet since that big squirt is what I needed to keep the smaller main jet for a perfect AFR on the fwy .
To stay fat at middle to WOT I go with a 6.5 to 7.5 power valve for a 11.60 / 1180 AFR with a 87 secondary jet . Now I have the best of both worlds lean cruise , good power for acceleration and fat bottom end .

Turns out I called Holly told them I was having issues with this carb they said it had a tech note to go up to a #35 squirter and use # 2 pump cam position for the hesitation problems this carb has can you imagine that .

 

Some random thoughts:
1) We're here.
2) We see GROSS incompatibility: OP went from a 2-bbl smog-dog to a Performer RPM. That manifold is just waking-up @ around 6500.
3) Whatever happend to punctuation?

 

Well no I can't spell but it never really hindered me in life 🤔 or from making a living .
That's the funny thing see you reach out to others for advice and you take what advice they're giving 90% that you will see on summit or jegs they will tell you don't buy the regular Edelbrock performer that's just weight savings go for the RPM that's the one that you want because you'll never reach 5,000 RPM with the regular RPM intake!.
There's probably a crap load of people on this website that would have agreed the same thing and even have the RPM on their 360/390 as well .

But thank you for answering though I posted that about a month ago and you were the first one to respond so you know what my hats off to you , I ended up figuring it all out by doing my own research and butt Dyno I do agree nobody should put the Edelbrock RPM performer on a 360/390 unless they have built heads a 460 crankshaft etc.
Now that it's on there I'm not going to take it off just because of that , I was just following advice from other people on jegs and Summit and I found out that yes it is a mix match no doubt 🧐 I lost mid range and the Stock crank on my 390 is never going to turn past 4,600 regardless .

My Random thoughts
1) never buy a used carb from someone without taking it apart in front of them I had used needle and seats and a #28 squirter when it should have had a #31. I was told and seen the carb was new it was but they took the new parts out and put old ones in were they thought I would never look on the spot .
2) that F " up my whole tuning process due to stuck secondary needle and seats leaky power valve etc .
3) don't trust internet tuners and follow there advice unless it's backed by facts 😁.

 

Rookie mistake.
Toss the leaky power valve: savvy tuners learned long ago that they have almost zero benefit on a street engine.

Here's what will make it ROCK: https://www.holley.com/products/fuel...es/parts/26-36

 

No actually the guy told me that it was new in the box I should have got the hint when he told me it was a 650 and I knew it was the 600 .
At the time that was my swap from a two barrel to a four barrel and I was trying to get it all tuned out I found out later digging into the car that the guy changed some things inside and used them for himself but he advertised the carb as new in the box which it was, but instead of a 31 squirt nozzle it had a 28 not a big difference there but he swapped the rear needle and seat to an old worn out used one in my float got stuck down and I had a lot of problems tuning the rear because it would run out of gas so fast in a wide open throttle Pull.

The rookie mistake was trusting others when they sell you something don't matter if it's brand new in the box some people like to take new things out of the card for themselves and put them on their other one that's a bigger CFM and then they'll stick you with the old needle and seats and different size nozzle squirter , thanks for the link though I appreciate your response.

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It's a 4160 not a DP and as far as your previous post about the RPM intake just waking up at 6,500 ? I beg to differ so it's sweet spot is 8-10k RPM ? a 335 HP gt 390 only rev to 4,700 not sure if you have the$ 4,000 roller rockers and stroker crank and cam to reach 6,500 a mildly built FE will see 5,000 to 5,500.maxing out at 6,000-6,500.
My comp cam is rated at 1500 to 5500 that's the exact same operating range as the Edelbrock RPM intake.

It takes a lot of peaks and tweaks and $$$ to get an Fe over 6,000 RPM you better have a hell of valve train you're certainly not going to get it with those little straight rail rockers better be rocking Rollers and a stroker crank to get that high .

 

Closed for review.

Update: cleaned up and reopened.