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-   -   Carb question. 850 vs 800 (https://www.offshoreonly.com/forums/general-q/344032-carb-question-850-vs-800-a.html)

bck 01-19-2017 05:25 PM

The formula MT posted agrees with the carb Pro Systems sold me, so they do seem to actually utilize the formula. If buying an off the shelf carb I'd be concerned with what it really flows verses what the advertised flow is. If you determine you need an 850 and buy one advertised as 850 is it really flowing 850 or...?

chancer540 01-19-2017 05:35 PM


Originally Posted by getrdunn (Post 4521074)
Anybody have any experience with


http://blp.com/cart/index.php?main_page=index&cPath=72

I like the 2 cicuit doms.

I have seen alot of them used on open dirt late model engines 20,000-40,000$ engines.

Would prolly be a great carb for big cubic inch marine engine if set up properly.
Very expensive though....cost could be a deciding factor though....
just saying.

vintage chromoly 01-19-2017 05:42 PM

I thought Holley "wet" flowed their carbs.

I thought carter / Edelbrock "dry" flowed theirs.

Anyone know about the quick fuels?

getrdunn 01-19-2017 06:06 PM

1 Attachment(s)

Originally Posted by chancer540 (Post 4521085)
I have seen alot of them used on open dirt late model engines 20,000-40,000$ engines.

Would prolly be a great carb for big cubic inch marine engine if set up properly.
Very expensive though....cost could be a deciding factor though....
just saying.

I was looking at a 1250 under 1k. But ya I also noticed they have some high end or at least high dollar carbs as well. Had to look twice at the price.

getrdunn 01-19-2017 06:37 PM

Carbs can act strange. One of the last dyno sessions I was involved with was very interesting. Was on a revved up 502 but nothing spectacular and we tried every carb under the sun it seemed. From 750's to 950's. Holleys, including hp's, mighty and speed demons, AED along with a couple others. Can't even remember all of them but the 830 speed demon with choke horn was flat out the best hands down. Really blew my mind. Was not what I expected. If I recall it was up by 10 hp over the others. Overall not a huge difference btwn all of them but was a fun test. The kicker is though on the water the holley hp950 responded the best, idled great and best top end speed. Just sayin... interesting how things can work out. What and how??? All I can say like it's been said before is going from the dyno to the water are two different gigs. May not always apply but definitely can. The guys tuning in the bilge I have respect for especially when their looking for that little extra power. It's there just gotta have patients.

True story on a 24 challenger with a so called baker engineering 500 hp engine I picked up 2 mph on same day with carb tuning only. Carb was an 850 holley dp. That was before all the afr widebands were so readily available and aware of.

mike tkach 01-19-2017 07:42 PM


Originally Posted by MILD THUNDER (Post 4521049)
Looks like an 870 CFM carb for the ZZ502 crate?

http://www.chevrolet.com/performance...02-deluxe.html

looks like bajachicken got it wrong.

LT1GMC 01-19-2017 08:31 PM

My crate engine 502 with Edelbrock oval port alum heads and moderate cam would turn 5900 rpm with the stock merc Weber/Edelbrock style 750 carb. Properly jetted of course, but it idled great and had great out-of-hole and mid-range too. Personally not a huge believer in extra big carbs. Throttle bodies are different, they don't have to have a vacuum signal to meter fuel.

Baja Rooster 01-19-2017 09:31 PM


Originally Posted by LT1GMC (Post 4521149)
My crate engine 502 with Edelbrock oval port alum heads and moderate cam would turn 5900 rpm with the stock merc Weber/Edelbrock style 750 carb. Properly jetted of course, but it idled great and had great out-of-hole and mid-range too. Personally not a huge believer in extra big carbs. Throttle bodies are different, they don't have to have a vacuum signal to meter fuel.

Pretty much identical to my set up: ZZ502 shortblock with Eddy RPM ovals but I put a QF850 on it. The supplier brochure said 750.


Originally Posted by mike tkach (Post 4521133)
looks like bajachicken got it wrong.

Not the first time nor the last. ;)

mike tkach 01-19-2017 10:32 PM

i am glad you have a good sense of humor.did you ever think about changing you,r screen name bajachicken?it has a nice ring to it.

Baja Rooster 01-19-2017 11:11 PM

Nah... it's actually already the "family/internet safe" version of a nickname, so there's nothing you can do to it that's worse than the original, lol. Baja actually has nothing to do with my mediocre entry level boat, but I spend months down in Baja on a motorcycle by myself.

Now back to our regularly scheduled programming, and the fact that I fear that my equipment may be too small. I can spin my 502 to 5600 with a QF850. Maybe my prop is to small. Something is too small somewhere, dammit.


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