Turbo 3.8 in H-body conversion with stick

[keithnh]

Looking for parts n pieces I will need. Have 84 3.8 with auto trans going into 78 Sunbird/Astre wagon with 4-speed. Need flywheel that will work (have correct bell for 78 with 3.8 ) . Original flywheel hard to find was thinking a 3800 flywheel might work or Firebird/Camaro if it fits inside the bell and allows cable clutch to work correctly. Would like to find a listing of items I need for a turbo conversion on this non-turbo 3.8 also. Am currently rebuilding a 450cfm Holley 4bbl 4360 to attach via Holley carb adaptor to Ken Bell #1 square bore intake.

1st conversion is 3.8 auto to stick
2cnd is 2bbl to 4bbl
3rd is to fuel injection tbi or dry carb - port injection
4th is to turbo

Need to keep car running as much as possible in between. Any help with parts or thoughts would be appreciated. Thanks Keith

 

[ttaowner]

I've got a couple 4 barrel intakes. A Weiand and a factory. Both are aluminum

 

[charlief1]

Orielly and autozone used to be able to order them. About $100 from what I remember. You can't use a 3800 because the flange is smaller and own't bolt up. You also need to be aware of the 2 clutch sizes. One uses a 9" disc and the other uses an 11" one. Oddfire also use a different balance so make sure it's an even fire unit.

 

[keithnh]

Have a Ken Bell #1 intake, just ordered adaptor to put spread-bore on its square-bore hole. Have a single 4360 450 cfm Holley 4bbl. 4360 a q-jet economy replacement effort, has very widely separated small mechanical secondaries that kick in sooner and don't have an air valve controlling flow. Keep mulling over that q-jet to square bore adaptor thinking "just get the correct squarebore 390 Holley" tho. But the 4360 was supposed to have worked well ... guess I will build both and see which works better. I have a thought for the 4360 on another motor as part of an Offy dual quad setup and just ordered a second. They are cheap because no one diddles with them. Small secondaries probably have less of a bog issue to conquer as q-jets do ( I rebuild them) 450cfm seems small but x2 = 900 cfm. Probably perfect for massive throttle response on the 444 Im also working. Wondering what makes a Holley 390 390cfm and if I could just change metering blocks on one of my spares. I think the Holley throttle body dimensions are identical.

Think there may be an even-fire internally balanced motor as well as one that requires an external modification to flywheel and possibly damper on snout ... it may be called a 231-A and this might be what is in my Cutlass. I want to get these correct as I may modify this low mileage motor externally to add power ... hopefully without having to tear it down and balance. My Chevrolet Power book says their V6's 78-85 are internally balanced with 2 pc crankseal .. in 1986 with the switch to 1 pc seal their V6's required an externally weighted flywheel. Not sure Buick did likewise ... Novak-adapt site that has a nice Buick V6 section says " The 231 even fire V-6 uses a differently balanced flywheel from the odd-fire engines tho both are externally balanced " The FW131 flywheel that shows fitting my 1980 Firebird 231 in Rock Auto also fits small block chevrolet V8 ... if this is true must be because its neutral balanced. Have a Buick book coming ... ???

 

[charlief1]

All of the factory installed stock RWD Buick V6 engines from 90 down are external balanced. They only did the internal design as racing or FWD. I can also tell you that the chevy 4.3 that was in my GMC was external balance. And a chevy book for dealing with Buicks will cause you more problems than you want to know.

These engines like a decent sized carb and spreadbore are the best. If you can find a 630 CFM Q-jet it will be very happy and give you more than enough power.

 

[keithnh]

If this was done so universally there must be a common modification done identically to whatever components are involved ... flywheel, damper, crank ... at least the external ones that might likely be changed, the crank being the one most likely to be adjusted individually. ?? I am changing the flex-plate to a flywheel and thinking my block may have 2 sets of bolt holes for the starter possibly a 153 tooth location and a 160 tooth. And if I get the 153 tooth FW131 flywheel that shows fitting numerous gen II Firebird 231's ( Buick motor) yet also sbc maybe I can have it drilled at machine shop in a standard weight reducing regimen if this is necessary. I might also splurge for a higher quality damper ... this would make sense anyway for better rpm ... if I can do it without disrupting anything a factory damper adds to balance. This motor is together and low miles ... don't really want to crack it open, maybe change the intake. Maybe the Buick book I've ordered will shed light on this.



Have a Ken Bell #1 intake made for squarebore. Supposed to be best intake for street strip 231. Ordered rebuild kit for my 6299-1 390cfm and the adaptor to fit 4360 carb to squarebore and kit. Will give both a try. Have a brand new Edelbrock 600cfm was thinking it would drown the 231. I think it is squarebore.

 

[charlief1]

It's not the ID of the flywheel or tooth count that matters here. It's the ID of the bolt pattern where the crank and flexplate/flywheel that's the issue. The earlier cranks used a 2 piece rear seal and the newer ones use a 1 piece seal, so the blot pattern is different. The newer ones have a smaller pattern and will not interchange with the earlier ones without an adapter of some sort.

The best intake for a Buick NA is a weiand but is very hard to come by. It's an open plenum design and the last one I found was in aussie land. Price was $320 aussie plus shipping ect.

 

[keithnh]

Just got my flywheel from Rock Auto LUK LFW131 153 tooth appears to have a 10 15/16 clutch face and 11 5/8 distance(diameter) bolt circle for pressure plate. there are 6 larger bolt holes flush to PP surface and 12 smaller holes approx. .075 below PP surface possibly for a recessed PP mount? A new universal cheap flywheel made in Mexico. Does have 6 fresh drill holes on backside so some sort of external pre-balance must have been attempted, may be that's what it took to be neutral, I hope not . It showed as being correct for 1979 Buick Century 231 V6. Have an 84 engine but no listings show for manual trans that year. I see a Sachs clutch kit K 167510 with 10.5 in PP for 84$ and an Exedy 10.5 04021 for 113$ Will see if bolt circle is an issue shortly. H-body bell housing may not take the larger PP, I think they were 9 1/2 ... will soon see on that as well.
I don't need the best intake really, just had this one among my parts along with a nice engine dressup kit. It will serve my purposes most likely with the 390 Holley 4bbl I also had. Will use the Holley first wet and maybe later as an air valve dry for port injection with this manifold. I see now with my Buick book Stage 1 and 2 blocks have desirable strengthening features that were incorporated in Turbo engines. Not really sure how "required" they would be to implement a street driven turbo setup. Extra head bolts on Stage 2 would be desirable to me although Stage 1 does not have them. The intercooler setup is completely external to the engine and as easily installed with a production block as a heavy duty block isn't it?.

 

[79bird]

Looking for parts n pieces I will need. Have 84 3.8 with auto trans going into 78 Sunbird/Astre wagon with 4-speed. Need flywheel that will work (have correct bell for 78 with 3.8 ) . Original flywheel hard to find was thinking a 3800 flywheel might work or Firebird/Camaro if it fits inside the bell and allows cable clutch to work correctly. Would like to find a listing of items I need for a turbo conversion on this non-turbo 3.8 also. Am currently rebuilding a 450cfm Holley 4bbl 4360 to attach via Holley carb adaptor to Ken Bell #1 square bore intake.

1st conversion is 3.8 auto to stick
2cnd is 2bbl to 4bbl
3rd is to fuel injection tbi or dry carb - port injection
4th is to turbo

Need to keep car running as much as possible in between. Any help with parts or thoughts would be appreciated. Thanks Keith

I have a Q-Jet off of a '79 Turbo Regal that I was going to put on my 4.1 Buick in my '79 Sunbird. It was rebuilt and has 3,000 miles on it according to the seller. Apparently it's the wrong carb for my NA motor. The card number is 17059243, 0419 CKD I can send pics if you want.

 

[keithnh]

Thanks for the carb offer, have a good 4 barrel intake and a pretty wide selection of carbs. Motor is still tight and uses no oil. 79000 miles. Remember it used a lot of gas and wasn't very respectable in power output although torque was enough to move it around ok. Was thinking when its pulled Id change the intake and carb and maybe add headers with a custom exhaust as it home is changing to H-body. Have to do something in the middle to push through more air and was just eyeballing turbo buick rocker shaft complete assy's offered by weberpowerproducts.com wondering whether they might have 1.65 ratio vs 1.5 and whether my stock heads would accommodate them. Thinking if the engine makes genuinely more power it might not have to struggle to move car about and mileage might actually not be impacted ... if I can keep my foot out of it Really not trying for a numbers matching effort have a 390 holley and 600 Edelbrock that correctly fit my 4 bbl manifold ... the 390 is bigger than the 600 in size ... that's weird. PM me with what you are looking for for carb ... at least Id know its right for application.