Hot Rod Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
23 Posts
Discussion Starter · #1 ·
I'm building a chevy 261 and I know it's not going to be that powerful. It's going into a 50 chevy sedan. What would happen if I were to strap a trubo on with eight pounds of boost? I was thinking since the compression is so low it would be a perfect canidate. Assuming the engine did except the stress what would happen to the rest of the drivetrain? It seems like the cluch wouldn't support it. Any ideas? I was thinking I could build square tube manifolds since that's basically what it has in it now.
 

·
Registered
Joined
·
2,384 Posts
turbo 261

I personally wouldnt recommend it. That engine was never designed for such a thing. Does the possibility of a ventilated oil pan mean anything? You would be far ahead to drop a 250 or 292 Chevy/ GMC 6 in it and have a far better engine. These are 7 main engines while the 261 is only a 5 main.
 

·
Registered
Joined
·
23 Posts
Discussion Starter · #3 ·
What is a vented oil pan? The reason I'm putting a 261 in is because it's a direct swap. what else would you have to do to put a 250 in? Why are they better engines?
In what way is the 261 not designed for turboing? I think that it has more potential for stress then it recieves.
 

·
Registered
Joined
·
2,384 Posts
turbo 261

A vented oil pan is what you wind up with when your rods and crank etc go through it when it disentigrates. The 261 is an old engine design, coming out long before all the whizz bang hi performance stuff came out and was basically a truck engine, designed for low rpm operation.
Its ok to build one up but they just arent a high rpm engine and wont tolerate a lot of cylinder pressure of the kind you are looking at with a turbo.

You would have to get with a more expert person on Chevy engines than me about what the swap would entail putting in a 250 or 292 I-6, but the 250 and 292 are modern design engines with 7 main cranks while the 261 is an old 5 main design. The 250 is also a lighter engine weight wise, and the 292 will weigh no more than your 261.
I am reconning that about all you would have to do is swap the bell housings and motor mounts to do the job. You might have to fabricate new frame mounts for the engine mounts. This could well be done by robbing them out of a vehicle that had the 250 or 292 in it. The 292 was used in trucks only, where the 250 was used in about everything Chevy built from 66 on up, that had an I-6 in it.

There are a lot of hop up parts on the market for both the 250 and the 292, where finding stuff for that 261, well good luck on that. The 250 and 292 are very receptive engines to modification and will easily put out 1 hp per cubic inch without turning stratospheric rpm, and do it on pump gas as well.
If you want to see stuff for I-6 engines, check out Clifford Performance. They are 6 pack gurus.

You would also need the appropriate flywheel as well as the bellhousing. Unless Chevy changed the bolt pattern for the transmission to mount to the bellhousing, there should be no problem there. I seriously doubt you would have to do any drive shaft work, since all three engines are relatively the same length and the transmission should not have to be relocated.

The 219, 235, 261 sixes all date their technology back to the late 20's early 30's, while the 250 block and 292 came out in the 60's.
 

·
Registered
Joined
·
5 Posts
Not sure I agree with Max on this. The 261 is a super engine and GM would probably be using most of its design today if the newer cars did not require a new shorter style engine to fit into the newer designed cars of today with the lower hood clearance problems and the want for lighter weight for the gas mileage. Yes it does only have five mains and not the seven. This is an excellent street engine that is actually a stiffer block than the lighter 250's. If you are talking a street engine and turning 5000 rpm or less, the the 261 would work. I have a 261 and have no problem finding hop-up equipment for it. You could actually stroke and bore it out, get forged pistons (speed equipment may be harder to find for the 261, but it is out there). Whichever way you go is up to you and your wallet. Just because something is old does not always mean that it is unsuitable. Any inline 6 cyl would be in danger above 5000 rpm's if you want it to last.
This is just my $.02's worth. The 261 was and still is a great engine.
 

·
Registered
Joined
·
2,384 Posts
turbo 261

In 69 and 70, I raced a limited sportsman stock car with a 240 cubic inch Ford 6 in it. That engine saw well over 7000 rpm on many a night, and unless there was a yellow or red flag it didnt get under 4500. Not too bad for 6 in a row with a basically stock lower end. All that had been done to the rotating assembly was balancing.
 
1 - 8 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top