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carb conversion questions

PostPosted: Mon Sep 07, 2015 10:41 am
by LuckyBaldwin
i have a '68 w100 w/ an LA318. the previous owner deleted the original 2 bbl carb and manifold and replaced it with a single plane, open plenum 4bbl manifold and holley 650 model 4160. guess he planned on racing circle track with it lol.

it ran ok once it was going but had a bad off-idle stumble. seems the butterflys on that big carb were closed so far to get the idle speed down, that the idle transfer slot was completely covered. i filed away the bottom of the butterfly enough to expose the slot and got rid of 90% of the stumble. i'm to the point that i can't expose any more of the slot without running the risk of it pulling gas at idle... that carb sucks anyway when i'm out wheeling, so i've decided to get rid of the 4bbl setup.

i found a 2bbl manifold/carb (BBD) off a '70 318 challenger that should work. i've heard bad things about going off road with a BBD, tho. i was thinking of going with a motorcraft 2100 instead. has anyone done this conversion? if so which 2100 did you choose (1.09, 1.14, 1.21)? and what vehicle did that size carb come out of? finally, does the 2100 bolt pattern match the BBD's? thanks!

Re: carb conversion questions

PostPosted: Wed Oct 14, 2015 6:15 pm
by swptln
Any Ford type 2bbl will not fit on a Chrysler manifold without some serious modifications. I don't see why a Carter BBD wouldn't work, I would take the Carter over the Ford type any day. If your doing serious 4-wheeling (high angles, rock crawling, etc.) all carburetors are going to have limitations, due to a carbs having to store fuel in a bowl with jets and floats, etc. If your doing serious 4-wheeling fuel-injection is the best.
Here's a Carter BBD 4-wheeling.
http://imageevent.com/terryandlinda/lee2005;jsessionid=95ylxha0a2.goose_s?p=68&n=1&m=-1&c=3&l=0&w=4&s=0&z=3
http://imageevent.com/terryandlinda/vtrally2004?p=43&n=1&m=-1&c=3&l=0&w=4&s=0&z=3

Re: carb conversion questions

PostPosted: Sun Nov 01, 2015 4:46 am
by LuckyBaldwin
thanks for the advice, Mark. you've convinced me, i'll try the BBD that came with the manifold.

i found that summit sells an adapter plate that will mount the 2100 to the smaller BBD carb flange. still is kinda like running a restrictor plate tho. that might make a replcement 2100 that flows too much more air than the BBD a real PIA to tune...

that coupled with your pics convinced me. thanks again Mark

lucky

Re: carb conversion questions

PostPosted: Mon Nov 02, 2015 3:38 pm
by WD
Get a 350cfm Autolite-Holley-Motorcraft with electric choke and a 318LA is a happy little engine. The Carter small block choke in the manifold is difficult to get parts for. Big block version is as common as the Chevrolet version, but, both those are "backwards" on an LA set up.

You can also run a Ford internally ballasted coil and ignition solenoid to delete the less than ideal Mopar system.

Re: carb conversion questions

PostPosted: Mon Nov 02, 2015 7:00 pm
by swptln
Ya, those adapters will create a lot of turbulence/stonewalling in flow unless you port match the manifold and plate. The choke thermostats are still available through a number of places if you do a search on them.

Re: carb conversion questions

PostPosted: Thu Nov 05, 2015 11:51 am
by WD
Then someone started repopping small block ones, because no parts store in 6 different states has been able to get them. Big block versions, no problem, small block versions come up as unavailable... :thinking

Looked online just now... ouch. Carb off a 302 is $10 at pull-a-part, adapter is cheap.

Re: carb conversion questions

PostPosted: Fri Nov 06, 2015 1:59 pm
by swptln
WD wrote:Then someone started repopping small block ones, because no parts store in 6 different states has been able to get them. Big block versions, no problem, small block versions come up as unavailable... :thinking

Looked online just now... ouch. Carb off a 302 is $10 at pull-a-part, adapter is cheap.


Ya, the adapters are cheap, but by the time you get done modifying the manifold and the adapter for it to work, you can buy 2-3 choke thermostats.
I've seen one of those adapter someone put on a 318 and the ports don't line-up and it looks like you might even have to weld up the intake in order to get the ports even close. The problem is the adapter has larger ports than the 318 intake, if it was the other way around it would work. :2cents

Re: carb conversion questions

PostPosted: Fri Nov 06, 2015 3:31 pm
by Hobcobble
There are plenty of decent used Carter BBDs out there. :idea
Get one that doesn't have a sloppy worn out throttle body, buy
a carb rebuild kit and you should be all set. I've rebuilt the Carter
and Stromberg carbs and they've been working well. :Thumbsup :2cents
John

Re: carb conversion questions

PostPosted: Fri Nov 13, 2015 10:32 pm
by PwrWgnWalt
:goodpost :goodpost

+1 what John said !!!

Re: carb conversion questions

PostPosted: Tue Nov 17, 2015 12:43 am
by LuckyBaldwin
finally got enough bench space to unpack the carb and manifold.

Nov112015 259a.jpg

hey! it has the choke too. that's lucky lol.
looks like it's the good type bbd.


this isn't so lucky tho...

Nov112015 262a.jpg

whada u think? leaky valve guide?

Re: carb conversion questions

PostPosted: Sun Nov 22, 2015 3:12 pm
by swptln
LuckyBaldwin wrote:finally got enough bench space to unpack the carb and manifold.

Nov112015 259a.jpg

hey! it has the choke too. that's lucky lol.
looks like it's the good type bbd.


this isn't so lucky tho...

Nov112015 262a.jpg

whada u think? leaky valve guide?


For sure, good carb and even better manifold, the X style manifolds are the best. I would definitely have those heads pressure tested.