SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: LBsuperjet on July 21, 2008, 06:55:55 PM

Title: carb sizing question::::
Post by: LBsuperjet on July 21, 2008, 06:55:55 PM
Alright gentlemen, before half my motor was jacked, i had twin holley 660 center squirters. i recently have found (2) 750 demons for sale at a sick deal! the seller says he had them on his 468 chebby...one person says ill be over-carbing my motor, another will say they will be just fine for what i have...problem is, i dont know the EXACT displacement, but i think its .040 over...it is a 460 ford somewhere in between stock 460 bore and 500cu. here's a pic of it with what i have as of right now, in case it helps.

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi89.photobucket.com%2Falbums%2Fk219%2Friverat84%2Ff28ee9c7.jpg&hash=7ad95d875675f68c0344e2b7e65a73229576fc2f)

i really wanna get this setup because its at a great price, and exactly what i need to get my ish running again.

thanx for the future help.

Reid
Title: Re: carb sizing question::::
Post by: pw_Tony on July 21, 2008, 07:04:43 PM
Honestly, on a Mild .030 Chevy with a Tunnel Ram... I gained performance and saved ALOT of gas from going from dual 650's to dual 450's double pumpers..... they're cheap, and work good....
Title: Re: carb sizing question::::
Post by: GT Jets on July 21, 2008, 07:14:55 PM
IMO, two 750's would be like two toilets flushing when you mash the gas, I would think with a T-ram, two 450's or even 600's would be more than needed w/o knowing the engine specs. I always say its way easier to overcarb than to under carb.

Unrelated, if you live in Long Beach WTF is the snowshovel for? :-\
Title: Re: carb sizing question::::
Post by: AA/Paul on July 21, 2008, 07:43:33 PM
If it's cheaper than buying new ones I'd run it. Jet it down. If you're lucky it has the replacable venturies.
Title: Re: carb sizing question::::
Post by: Luckie Stiff on July 21, 2008, 07:55:17 PM
If it's cheaper than buying new ones I'd run it. Jet it down. If you're lucky it has the replacable venturies.

That's what I told him to do, his engine is a stroked 460, how stroked nobody really knows, but in it's old form with the 660's it ran 92MPH (according to the old owner) and I think prospect said he's had it to 85. 
Title: Re: carb sizing question::::
Post by: rogers tr on July 21, 2008, 08:57:27 PM
2 750s would depend on cam and heads?
Title: Re: carb sizing question::::
Post by: Luckie Stiff on July 21, 2008, 09:04:05 PM
I know the heads are cleaned up D3's no idea on the cam.
Title: Re: carb sizing question::::
Post by: rogers tr on July 21, 2008, 09:18:19 PM
the cams important what rpm do you want it to run at how cleaned up a little or a lot
Title: Re: carb sizing question::::
Post by: LBsuperjet on July 21, 2008, 09:39:44 PM
ive had it to 5800RPM, and i have no clue about the cam specs, all i know is that its huge lol...

its just a sweet chance at a sweet deal, and they even come with a clean dooley scoop, all quite new. i wouldnt mind finding smaller carbs, but nothing is for sale in a used good pair right now, i slacked on a couple deals from jim brock because i was spending my mula on other shit.. should i just buckle and get 2 edelbrock 550's?  :screwy:

thanx for the info gents,

Reid
Title: Re: carb sizing question::::
Post by: LBsuperjet on July 21, 2008, 09:41:12 PM
IMO, two 750's would be like two toilets flushing when you mash the gas, I would think with a T-ram, two 450's or even 600's would be more than needed w/o knowing the engine specs. I always say its way easier to overcarb than to under carb.

Unrelated, if you live in Long Beach WTF is the snowshovel for? :-\

dude, i really dont know, its my parents, and ironically ive never asked  ;D
Title: Re: carb sizing question::::
Post by: lilrick on July 21, 2008, 09:45:28 PM
ditch the ram and put a single 850 on it .
Title: Re: carb sizing question::::
Post by: LBsuperjet on July 21, 2008, 10:00:05 PM
ditch the ram and put a single 850 on it .

thats what most ppl are telling me to do...then i need a victor.
Title: Re: carb sizing question::::
Post by: crewchief22 on July 21, 2008, 10:10:53 PM
ive had it to 5800RPM, and i have no clue about the cam specs, all i know is that its huge lol...

should i just buckle and get 2 edelbrock 550's?  :screwy:

thanx for the info gents,

Reid

I wouldn't recommend the Edelbrocks for your application.

If nothing else comes up, get the 750's and run it, if its too much sell them and pick up a pair of 660's (you know they worked). 
You already said that you can get a good deal on the 750's so if you sell them you might be able to make an extra buck.
Title: Re: carb sizing question::::
Post by: GT Jets on July 21, 2008, 10:37:52 PM
If the deal is that good, buy them, and keep your eyes open for someone looking to trade up or F-it, bolt em on and see what happens, those Demons are pretty flexible as far as parts swapping, another funny thing you could do is jet them down and put some restrictor plates under them to get them to the cfm range you're looking for, a little hokey, but it would keep people wondering >:D
Title: Re: carb sizing question::::
Post by: LBsuperjet on July 21, 2008, 10:58:44 PM
If the deal is that good, buy them, and keep your eyes open for someone looking to trade up or F-it, bolt em on and see what happens, those Demons are pretty flexible as far as parts swapping, another funny thing you could do is jet them down and put some restrictor plates under them to get them to the cfm range you're looking for, a little hokey, but it would keep people wondering >:D

good idea!...ill check it out then, ill just have to feel it out...thanx for all the good advice guys.

Reid
Title: Re: carb sizing question::::
Post by: Luckie Stiff on July 22, 2008, 06:02:36 AM
ditch the ram and put a single 850 on it .

What he said.
Title: Re: carb sizing question::::
Post by: GAWnCA on July 22, 2008, 07:25:48 AM
Unrelated, if you live in Long Beach WTF is the snowshovel for? :-\

That's not a snow shovel, it's just a scoop shovel.

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fgregaw.home.comcast.net%2Fscoopshovel.jpg&hash=afac641a8770a27d18ed4869fc5eaffb0cbb12b4)

This is what a snow shovel looks like.   ;)

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.uline.com%2Fimages%2Fproduct%2FMedium%2FHD_7052_M.jpg&hash=b970b2b47f6878dc796ea41d6e35fcf0934a99d5)
Title: Re: carb sizing question::::
Post by: GT Jets on July 22, 2008, 08:02:57 AM
That's not a snow shovel, it's just a scoop shovel.

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fgregaw.home.comcast.net%2Fscoopshovel.jpg&hash=afac641a8770a27d18ed4869fc5eaffb0cbb12b4)

This is what a snow shovel looks like.   ;)

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fwww.uline.com%2Fimages%2Fproduct%2FMedium%2FHD_7052_M.jpg&hash=b970b2b47f6878dc796ea41d6e35fcf0934a99d5)

Thread jack; in the midwest, thats a scoop shovel, here in California (speficically at a cabin in Tahoe) thats a snow shovel, because we never use the right tool for the job ;D
Title: Re: carb sizing question::::
Post by: GAWnCA on July 22, 2008, 08:13:46 AM
Thread jack; in the midwest, thats a scoop shovel, here in California (speficically at a cabin in Tahoe) thats a snow shovel, because we never use the right tool for the job ;D

No wonder you are always working on your boats.   ;D ;D ;D  Do you use the right parts? ??? 
Title: Re: carb sizing question::::
Post by: LBsuperjet on July 22, 2008, 08:17:28 AM
hahaha
Title: Re: carb sizing question::::
Post by: HDriderTH on July 22, 2008, 09:03:17 AM
Alright gentlemen, before half my motor was jacked, i had twin holley 660 center squirters. i recently have found (2) 750 demons for sale at a sick deal! the seller says he had them on his 468 chebby...one person says ill be over-carbing my motor, another will say they will be just fine for what i have...problem is, i dont know the EXACT displacement, but i think its .040 over...it is a 460 ford somewhere in between stock 460 bore and 500cu. here's a pic of it with what i have as of right now, in case it helps.

(https://www.socaljetboats.com/proxy.php?request=http%3A%2F%2Fi89.photobucket.com%2Falbums%2Fk219%2Friverat84%2Ff28ee9c7.jpg&hash=7ad95d875675f68c0344e2b7e65a73229576fc2f)

i really wanna get this setup because its at a great price, and exactly what i need to get my ish running again.

thanx for the future help.

Reid

Get the Demons they'll work great. Over carbed, I run two 1050's.
Title: Re: carb sizing question::::
Post by: pw_Tony on July 22, 2008, 02:19:53 PM
I thought this motor was only 400-450 hp? Unless you've changed the motor?  :sly:

I wouldn't get 660's..... otherwise known as lightswitches  ;D I have a pair, and have tried them on a N/A motor and I think they work much better on blown

What impeller do you have?
Title: Re: carb sizing question::::
Post by: LBsuperjet on July 22, 2008, 02:29:26 PM
I thought this motor was only 400-450 hp? Unless you've changed the motor?  :sly:

I wouldn't get 660's..... otherwise known as lightswitches  ;D I have a pair, and have tried them on a N/A motor and I think they work much better on blown

What impeller do you have?
its the same motor...closer to 500hp. i had twin 660 center squirters on it the way it all came, and it ran PERFECT! so i figured as long as i get something close, ill be fine. i dont know about my cut on my impellar...its a full aggressor pump maybe AA or A??

Reid
Title: Re: carb sizing question::::
Post by: pw_Tony on July 22, 2008, 02:39:55 PM
And your boat turned 5800rpm? Something just doesn't add up to me
Title: Re: carb sizing question::::
Post by: LBsuperjet on July 22, 2008, 03:32:14 PM
And your boat turned 5800rpm? Something just doesn't add up to me
yeah i think i have...i may be wrong but above 5300 for sure. i was going fast and just had time to glance...

nonetheless, i really wanna get these just because i know they're more than enough for my motor to run right, i just wanna make sure its not too much, and that the "demons are hard to tune" saying could be put to rest. no racing here, just cruising, but i also want to keep my TR, just cuz i put alot of money into it buying it and getting it coated.

Reid
Title: Re: carb sizing question::::
Post by: GT Jets on July 22, 2008, 11:15:57 PM
good idea!...ill check it out then, ill just have to feel it out...thanx for all the good advice guys.

Reid

My buddy turned me on to these, a little pricey and sort of a tool but might work ??? He is a dynomometer operator in Grants Pass Ore.

http://store.summitracing.com/partdetail.asp?autofilter=1&part=WCD%2DWCD8850&N=700+325405+115&autoview=sku
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