I just put a 650 holley carb on my 85 gmc pickup with a 305 engine, seems like it has no pickup, idles great but sluggish....should i tune the timing some....thanks
Might be a little too much carb cfm for a stock 305. I've got a 305 with a RV cam aluminum intake and a 600 and it's a fresh motor and it doesn't have much pickup at all.
>Might be a little too much carb cfm for a stock 305. I've >got a 305 with a RV cam aluminum intake and a 600 and it's a >fresh motor and it doesn't have much pickup at all. Sorry but Holleys are always a pain in the ###. most of them even on a strong motor will only pull 525cfm.The floats wil not adjust right without a fuel regulator, run it at about 5lbs to start. I had a 650 on a 350hp vette. couldnt hardly spin the tires without high revs. I rebuilt a stock Rochester and I could light them up in 2nd gear just by squeezing the pedal down.Rochesters look confusing but with a little time tuning they'er great. Oh yeah if I kept my foot out of it I got15mpg......
Edelbrocks and Rochesters are definetly better carbs then the junky holleys.Karl ________ HOW TO ROLL A JOINT
Although I'm just a young one, I have to agree about the inferiority(spelled right?) of Holley carbs. I've grown up working with my father in a shop, and watch many a h.olley carb be ripped from a truck for the scrap metal in favor for an edelbrock. just my two cents. -ML
Yes I put a Edelbrock on all of my vehicles, you just can't beat the carb for everyday driving without having to adjust it all the time. It always runs good.
Hi all, my Rochester M4V4 -which came with my 1978 Silverado- keeps dripping on the left side (1st step?). Is there a general known answer for this? Willem +31 402230006
when you say "dripping" on the left side, where at? Depending on how old or miles are on the carb it could be that the shafts that open and close the butterflies have worn out the hole on the carb base plate. If you can grab the shaft and move it side to side or up and down its time for a fix. There are carb shops that can drill out the base plate and install bushings. Or you coulde have a gasket leak...
Hello Knuck32, It sounds like it is running a bit rich to me. I am in the minority (it apears) here, but I find the adjustability of the Holley a wonderful benifit. In just a few quick minutes, I can adjust everything. I agree they are not perfect, but neither are any of the others. All (well at least most) Holley's require adjustment to your style of driving and your engine. If you spend the time to understand the particulars of your performance characteristics, you can quickly and easily adjust the Holley to meet your needs. I believe that Quadrajets work better "out of the box" with little or no adjustment for around town applications. Quadrajets seem to have a slight edge on economy, but in my circle, the Holley has the advantage when it comes to performance. With that said, I do know that it takes some effort to get it just right. I don't want to start a war, I just think everyone should have an open mind. Tom
Well, it's not so much that it is "too much carb" as someone indicated, but it is probably too much fuel. Cant really have too much carb as you can only have too much air if there is not enough fuel. Check your mixture adjustments and idle mixture adjustments. I try not to tell anyone that I dont like the brand that they are using, but I will tell you that I too have had great experiences with rochesters. I bought an old Q-jet spreadbore on ebay for $13 and have been running it ever since (probably about 4 years now). It gets good gas mileage when I stay out of the secondaries, and hauls booty when I open the secondaries. It was very easy to adjust, and stays adjusted very well. I also do not need a regulator to avoid problems with overflowing the floats.
