Changing to Holley
#11
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Re: Changing to Holley
Originally Posted by Whiteknuckle
I don't want to keep sounding negative, but an 850 CFM is a little large for your engine. You may not like throttle response. A 750 or 800 at the largest would work a lot better.
I agree
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Re: Changing to Holley
Originally Posted by cuda
I'm pretty sure all the Q jets were 750's. Just different metering rods.
Yep...that is the only difference if i remember correctly
#13
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Re: Changing to Holley
Like 40 bucks for a edelbrock tuning kit for that weber will help you fatten it up and get those plugs a nice shade of brown again. Edelbrock are the same as the weber. Went through this in the summer with mine. Lots of info on them on the site. Why spend all that money on new carbs and have to tune them too cause they probably won't be dead on out of the box. The webers are much easier to tune , change of the metering rods takes like 5 mins and no removal of the carbs.
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Re: Changing to Holley
Originally Posted by cuda
I'm pretty sure all the Q jets were 750's. Just different metering rods.
Yep...that is the only difference if i remember correctly
#15
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Re: Changing to Holley
Before you make the guy not use this Holley, there are some unknowns here:
1) He stated this 850 was done by Nickersons for, and installed on, a 454. Whaqt kind of mods and what build up for this 454 ?
2) He stated he has a 502 but not which HP one, nor if any mods have been done to it.
1st Baja - give us more info and we can help, or better yet, get all info on the 454 (incl owners name so Nickerson can look it up) and all info on your 502 and call Nickersons to see what changes may need to be done.
2nd guys - a high performance dual plane intake can use a bigger cfm carb than a single plane. Reason - more signal. Just like why many mild (350-400hp) SBC's with dual plane's prefer 750's.
1) He stated this 850 was done by Nickersons for, and installed on, a 454. Whaqt kind of mods and what build up for this 454 ?
2) He stated he has a 502 but not which HP one, nor if any mods have been done to it.
1st Baja - give us more info and we can help, or better yet, get all info on the 454 (incl owners name so Nickerson can look it up) and all info on your 502 and call Nickersons to see what changes may need to be done.
2nd guys - a high performance dual plane intake can use a bigger cfm carb than a single plane. Reason - more signal. Just like why many mild (350-400hp) SBC's with dual plane's prefer 750's.
#16
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Re: Changing to Holley
Originally the boat came with a 454. The guy swapped out the 454 with a 502 crate motor. I don't know if it's a Mercruiser 502 or a GM crate motor (not sure how to tell). I was told its a Gen VI motor.
When the guy swapped motors, he ended up using the original carb. I sent that out to the carb shop to see if they could do anything with it. They said it was an AFB carb built by weber (625cfm). Nothing they could do with it to increase cfm.
So I gave Nickerson a call about it and they set me up with this Holley 850. Looks like a nice unit. They said I can bolt it right up to the mercruiser manifold and I won't have any problems.
So I'm going to install it this weekend and see what happens.
When the guy swapped motors, he ended up using the original carb. I sent that out to the carb shop to see if they could do anything with it. They said it was an AFB carb built by weber (625cfm). Nothing they could do with it to increase cfm.
So I gave Nickerson a call about it and they set me up with this Holley 850. Looks like a nice unit. They said I can bolt it right up to the mercruiser manifold and I won't have any problems.
So I'm going to install it this weekend and see what happens.
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Re: Changing to Holley
So I got the Nickerson Holley 850 bolted up to the 502 over the weekend and tested it out. What a difference. Great midrange power over what I had plus I got the boat up to 61 mph GPS with 1,000 lbs of people and tools along with 90 gallons of fuel. Beat my last best of 59 mph GPS. Now I need to work on the prop a little bit. I have an old Mirage that is pretty beat up.