HELP 4.1 intake on 231 v6

R

RichmondNative

Not-quite-so-new-guy
Dec 26, 2018
12
8
3
#1
So I’ve read about swapping the intake manifold over from the 4.1 to my 3.8. Was planning on putting an adapter plate to bolt on a better carb. Just wondering if anybody had any tips or guidelines to follow. Any other parts I should get? Hei distributor?
 
MrSony

MrSony

Comic Book Super Hero
Nov 15, 2014
4,331
2,663
113
Des Moines, Iowa
#2
Just keep the computer stuff if its working fine. Too much hassle for a v6 to change anything.
 
spidereyes455

spidereyes455

Greasemonkey
Mar 6, 2013
243
198
43
Northeastern PA
#3
My advice is don't bother I did it about 20 years ago and I swear it made the car slower, and use a lot more gas. Even if it didn't make it slower there was certainly no improvement in performance.
 
olds307 and 403

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,775
1,648
113
Melville,Saskatchewan
#4
I am surprised to hear that. I know guys with the lousy 260 using a SP2P intake and a Qjet noticed a difference. If I still had that intake it would go on. I know shorty headers and 2.5" dual exhaust made a big difference on the 260 and should on the 3.8 as well.
 
pagrunt

pagrunt

Comic Book Super Hero
Sep 14, 2014
3,160
3,414
113
Shelocta, Pa
#5
Outside of a Q-jet maybe the best carb would be a 600 cfm or less that might make a slight improvemnt to power. Even just putting a 2.25" exhaust on could be of some help. Might just be one of those engines/intake combos that minimal up grades would work better than going bigger.
 
R

RichmondNative

Not-quite-so-new-guy
Dec 26, 2018
12
8
3
#6
Outside of a Q-jet maybe the best carb would be a 600 cfm or less that might make a slight improvemnt to power. Even just putting a 2.25" exhaust on could be of some help. Might just be one of those engines/intake combos that minimal up grades would work better than going bigger.
600 was what I was going for. Followed by swapping out the timing chain and headers after that. Not looking to rip mad skids just slight improvements for the daily while I save up for the big horsepower swap
 
Clone TIE Pilot

Clone TIE Pilot

Royal Smart Person
Aug 14, 2011
1,868
501
63
Galaxy far far away
#7
Best carb would be the special Buick V6 Qjet. Altogether, the 4bbl swap only adds 10 hp. Changing the rear axle gearing would be more effective.
 
olds307 and 403

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,775
1,648
113
Melville,Saskatchewan
#8
A 2004R or even a 700R4 for it's 3.06 first gear along with a adapter plate and 3.42 and up gearing will make a big difference. A 390 Holley or 500 cfm AVS2 with tuning or the best bet, a Buick special 4.1 Qjet, betting it is restricted in cfm. A 600 cfm is way to big for a 3.8, it would need a ton of tuning and still be too much. I would have transferred the Duajet's primary metering rods and APT position over to my a Qjet, along restricting the secondary air door and playing with secondary rods on my 260 if I had a SP2P intake still. The 4.1 Qjet might be slightly richer, which is good if adding headers and dual exhaust, which will also help. The headers and duals felt like 20 hp/tq on my 260, especially up top. With the 4bbl, it would be in vin Y 307 territory with slightly better mileage, in theory. Just expect a small improvement, a 8 to 1 small ci and cam motor can only do so much. Pushing in too much air and fuel will overwhelm it and hurt performance.
 
olds307 and 403

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,775
1,648
113
Melville,Saskatchewan
#10
The best "upgrade" I made to my 3.8 was replacing the old, lazy O2 sensor.
If you add headers, a heated O2 sensor upgrade is a good idea.
 

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