Guest Posted December 23, 2014 Share Posted December 23, 2014 (edited) I have a couple 4 barrel intakes for 1952 Roadmaster and one poorly brazed factory exhaust heat riser/choke stove. I had heard that the intake can be mildly modified to accept the center exhaust from the 2 barrel 320 cubic inch engine. I finally found someone who had done it and explained it to me. I'm posting cuz others have asked me about this too. The pics will hopefully explain if my words don't do it. Started out drilling two of the carb attachment stud holes out to 17/32", the hole size is to accommodate installing a chunk of 5/8" threaded bolt shank. The 5/8" bolt shank must be drilled and tapped for the 5/16" stud to thread into. I put a 5/8" bolt in my bench vise and drilled and tapped it, then cut 2 pieces approx 1/2" long to adapt to the holes drilled out and tapped for the 5/8" thread of the adapters. Next I turned the intake upside down and drilled the threads from the holes directly beneath the drilled out carb stud holes. This allows two 3/8" Allen socket head screws to be dropped thru the carb stud holes drilled out larger(the heads of the Allen screws need to be ground very slightly smaller od to fit)to accommodate this mod. After tapping the enlarged carb stud holes with 5/8" tap, screw the 5//16" carb attach studs(new in my case, didn't have any) into the 1/2" long 5/8" bolt shank pieces and then wire feed weld the bottom of the 5/16" stud where it shows thru flush with the bottom of the 5/8" adapter. Using the two 3/8" Allen head bolts thru bottom of intake and one more thru the two barrel stove choke tighten these three bolts with a new gasket and you have a usable 4 barrel intake with 2 barrel exhaust center section. Next I used Teton tape on the 5/8" adapters w/5/16" studs for carb attachment with two 5/16" nuts opposing one another, creating a temporary bolt head to screw the adapters into the larger 5/8" theaded holes with the studs up. Unlock the opposing 5/16" nuts. Ready now to bolt on carb or wait for beautiful NOS 4 barrel exhaust center which sells for 1500.00. Pics to follow. Thanx so much to Scott K. Edited December 23, 2014 by Guest (see edit history) Link to comment Share on other sites More sharing options...
Buicknutty Posted December 24, 2014 Share Posted December 24, 2014 So, is your plan to go to a single 4 bbl on your straight 8, instead of the dual 2 bbl's? This sounds like quite the procedure, but should be worth the bother when you're out and running, thanks for sharing. Keith Link to comment Share on other sites More sharing options...
PONTIAC1953 Posted December 24, 2014 Share Posted December 24, 2014 the original post says nothing about a dual two barrel intake. talks about a exhaust center section from a two barrel 320 engine. Link to comment Share on other sites More sharing options...
Buicknutty Posted December 24, 2014 Share Posted December 24, 2014 (edited) the original post says nothing about a dual two barrel intake. I know, but many early '40s Buick used dual carbs, working similar to a single 4 barrel, and I'm thinking that the OP is planning to used the 4 barrel instead of the more common upgrade (if not originally installed) of using the factory duals. I'm only asking as this would seem to be the intent, and am curious what the current setup is on the car. I have been considering a similar conversion on my dual carb '41, and am interested in what others are doing in this regard.Keith Edited December 24, 2014 by Buicknutty grammar (see edit history) Link to comment Share on other sites More sharing options...
Guest Posted December 25, 2014 Share Posted December 25, 2014 My original intent when I got the '41 Cent from my friend Dave T. was to find out engine condition by attempting to start and run the engine with the single carb it was wearing when acquired. First thing found was a rocker arm assembly put together incorrectly, noticed becuz the push rod was rubbing on the side of the hole in the head. Cleaned and found my spare also assembled incorrectly. 3rd times a charm with new lifters and .040 head mill ran great! Not wanting to worry about trying to keep stock twin 2 barrel system running reliably, I found my stock 1941 spare Cent engine had adapters with 4 bolt 1965ish Rochester 2 barrels installed on the dual carb intake. I purchase Rebuild kits at O'Reily auto(one major reason for carb choice)and installed in carbs. Engine seems to like them. Made linkage which opens them at same time. No black smoke or sooty spark plugs. Haven't put my Lambda sensors(fuel/air gauge) in the headers yet, but good indications are keeping me from drilling access holes that later need to be plugged. I am going to run the 4 barrel intake that I outfitted with the 2 barrel exhaust parts, but prolly not on the '41. I like Buick engines and the spare '41 Cent and the spare '40 Roadie engine don't have manifolds cuz I sold a beauty off the '40 to Mike Simpson in CO for his project and the dual from the '41 engine is on the '50 engine in the '41 Cent. Mainly wanted to see if I could get 'er done! Now, I'll put it on the '40 320 I know runs well then prolly put a Edelbrock to see how that works. They also make self tuning fuel injection that bolts on a 4 barrel intake and who knows where that could lead? Luck favors a curious mind, but I'm getting' short on years for experimental projects! Keep on! Link to comment Share on other sites More sharing options...
FLYER15015 Posted January 7, 2015 Share Posted January 7, 2015 Hi Greg,It is cold and snowy here in Colorado.The "Baby" is safely tucked away for the winter. See attached.Wanted to ask you if there is a need out there for the 3 piece exhaust manifold castings for the big motors, in something other than cast iron.I was thinking of 416 stainless steel.Once the patterns are made, you can pour almost any alloy into the sand.Your thoughts please.Mike in snowy Colorado Link to comment Share on other sites More sharing options...
Guest Posted January 18, 2015 Share Posted January 18, 2015 I'm thinking absolutely, stronger flanges=better because if I'm gonna spend some bucks and the labor I'd like to know I dont have to be so darn carefull with a crack if it's merely a little out of alignment and I can move it a bit or disassemble if need be. I have some I'm afraid to take apart cuz they are rust "welded" together and They may break if realignment needs doing when reinstalled! I'll take two at least for my two Four barrel intakes, or if someone wants to buy my stock one complete with carb and linkage and the jigsaw puzzle of an original 52 center exhaust piece all bazed together, knock yourself out. It's available!UOTE=FLYER15015;1382806]Hi Greg,It is cold and snowy here in Colorado.The "Baby" is safely tucked away for the winter. See attached.Wanted to ask you if there is a need out there for the 3 piece exhaust manifold castings for the big motors, in something other than cast iron.I was thinking of 416 stainless steel.Once the patterns are made, you can pour almost any alloy into the sand.Your thoughts please.[ATTACH=CONFIG]289745[/ATTACH]Mike in snowy Colorado Link to comment Share on other sites More sharing options...
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