Anybody using a spreadbore Holley?
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Anybody using a spreadbore Holley?
I have been having problems with both my Quadrajets that I can't fix myself so I decided to TEMPORARILY install a 650cfm. vac secondary Holley spreadbore. Got it from Summit - $375 plus shipping, plus instal kit, plus throttle cable bracket plus flat base air cleaner. I will be installing tomorrow to be ready (I hope) for Sat. Corvette Challenge race at Englishtown - made it to the 4th round last race on June 6. Had problems then so I was only running 13.0s, but consistent. Anybody have any advice for me? Thanks.
Drifting
Joined: Aug 2008
Posts: 1,381
Likes: 11
I have 2 of those carbs running on vehicles. I have one on a '79 vette - L48 with headers, dual exhaust, stock cam, 1.6 roller rockers, stock intake, running 38 deg. total timing. Carb works great. I jetted it down 2 sizes in the front and use the short yellow secondary spring (stock). Gas mileage is 1.5 mpg less than Q-jet and performance is equal. Installation was a snap - about 45 mins. - everything hooked right up. Just had to run a wire to the electric choke.
2nd one is on a Pontiac 400. Running just as it came out of the box at it works great. Again, the installation was very easy. This car is mostly stock (214/224/112 cam, headers, roller rockers, stock intake & heads) and makes 283 HP and 364 trq at the rear wheels. Runs consistent 13.7s @ 102 mph. How bad can it be?
2nd one is on a Pontiac 400. Running just as it came out of the box at it works great. Again, the installation was very easy. This car is mostly stock (214/224/112 cam, headers, roller rockers, stock intake & heads) and makes 283 HP and 364 trq at the rear wheels. Runs consistent 13.7s @ 102 mph. How bad can it be?
CF Community Team
Joined: Oct 2004
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From: Cape Cod, Mass.
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I'm running a Holley 650 spreadbore with mechanical secondaries on my otherwise stock 68 427/390. Great throttle response and low and mid range torque. I rarely rev it over 5500 RPM's so it works well on the big block. I did have to clean up some metal pieces in it from some incomplete machining at the factory. NOT too pleased with that, but it performs very smoothly now. It will sit a little higher than the Q-Jet. Hopefully hood clearance is not an issue on your car.
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
capevettes - I didn't see evidence of any leftover particles from the factory, so maybe I lucked out there. You're right about the height, the Holley is 1/4" taller than the Qjet.
BTW - Is there an internal gas filter in the Holley?
BTW - Is there an internal gas filter in the Holley?
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
I am running the 4175 Vac Sec model. Performance is good...gas mileage not so good. the secondary idle adjustment is a PIA....but all in all it's a very good carb for me...
I believe it will take the QJ style internal filter. I chose to run external inline filter.
I believe it will take the QJ style internal filter. I chose to run external inline filter.
Pro
Joined: Mar 2009
Posts: 703
Likes: 2
I bought Summits carb, which is actually made by Holley and after some fine tuning it runs very strong and hard for a VS carb. Initially I was very frustrated with the "out-of-the-box" performance and thought I had severe carb problems so I went out and bought a brand new BG Mighty Demon but I havent even installed it yet because this carb now runs so good.. Based on my previous 10.80 Camaro, I would say this car should easily run mid to high 12's and hopefully low 12's or possibly high 11's after a gear swap..
CF Community Team
Joined: Oct 2004
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From: Cape Cod, Mass.
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Mine has that perforated brass like filter where the inlet to the carb is located. I still run the factory inline filter as well.
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Team Owner
Joined: Sep 2006
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From: Westminster Maryland
Hi BK,
I've had a Spreadbore on my 350/270 since 1971. It has mechanical secondaries which took a little bit to get use to but I've always liked it.
You can see it in this picture, it even has the CEC solenoid on it. It was designed to be a direct replacement for the QJ.
Regards,
Alan
I've had a Spreadbore on my 350/270 since 1971. It has mechanical secondaries which took a little bit to get use to but I've always liked it.
You can see it in this picture, it even has the CEC solenoid on it. It was designed to be a direct replacement for the QJ.
Regards,
Alan
Thread Starter
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
Thanks for the info, guys. Here's the update. I just got back from a local cruise nite and the car is running real good. I made a couple approx 1/8 mile test passes on a nearby lonely road. However, I'm not using the Holley. First there was a gas leak at the inlet fuel nut. I replaced the original gasket with a similar one, then a plasic type gasket and finally a copper one. That stopped the leak. A test drive at that point was disappointing. Power level was down. I was desperate, so I decided to switch back to a Qjet. I took the air horn off my Lars Qjet and replaced the float - the car had been dying at full throttle. Installed it, started the engine and the carb seemed good so far but the engine just didn't sound right. Investigated and found a burned plug wire and boot under the header tube at #5. I fixed that a now all is good, with the Qjet in place. (except for the money sunk into the Holley) I'll see for sure on Saturday.
