4 barrel on a 292 straight six. Done it?

Some great info on here guys, I am looking to get something more efficient than my 1BBL - not fussed about power (first time I've ever said that - must be getting old). I was looking at this: https://www.affordable-fuel-injection.com/product/chevrolet-tbi-complete-system/#_form_7 - has anyone tried it? - Not intending to hijack the thread, thought it may be helpful.

What about a Holley 500 cfm 2300 2-barrel?

https://www.holley.com/products/fuel_systems/carburetors/performance_2_barrels/

I was getting 21 mpg consistently with my 250 CID, Carter YF 1bbl, 215 70 15 Michelins on all wheels, 3.08 rear axle and 3 speed with OD.  This mileage was obtained several times on highway runs from Sacramento, CA to Tacoma, WA. and back. It was Interstate 5 all the way and included some mountain driving.  When I installed a 3.23, my MPG dropped to 18.  I am planning to install a 292 also and will keep the OD.  I make OD transmission hanger brackets to mount the OD trans the same way the original was.  This avoids the long frame to frame cross member type trans mounts.  This is handy if you already have exhaust pipes running under there that might get in the way of an added cross member type mount.  Personally, I am not convinced that increasing top end breathing on a 292 will increase fuel economy.  I plan to go the other way; gear up with a 2 series rear axle so that the engine RPM can stay lower at highway speed.  The higher torque 292 should be also be able to handle that taller gear combination from a dead stop.  Three ring transmission will also help that.  IMO, the lower you keep the engine speed, the better the chance for improved MPG.  My goal is to get better mpg with the 292 than I did with the 250. We'll see how that works out.
108VanGuy...

108VanGuy wrote:  I make OD transmission hanger brackets to mount the OD trans the same way the original was.  This avoids the long frame to frame cross member type trans mounts.  This is handy if you already have exhaust pipes running under there that might get in the way of an added cross member type mount.

  I have always preferred fabbing a bracket and hanging the trans too, but gave in and ordered a crossmember and made brackets to install yesterday. with a stock engine, highway gears and cast iron tranny, I would keep the hanger but double the h.p. triple the torque and lower the gears and it swings around a bit. to make matters worse, I lowered the engine/trans an inch for the 292 to fit. this is what could happen. after that, I choose to loop around the tranny and bolt a mount on the factory location but that just amplified the swinging.  

Do you believe the cracked transmission case shown is due to the type of transmission mount used?  I have seen that type of failure before when a too long driveline was installed.  The suspension shortens the distance between the rear axle and engine/trans on big bumps causing the driveline to be forced into the back of the trans.  The back of the trans looks solidly mounted so the force could be transferred to the spot just forward of that.  The motor mounts would have some flex to them but could get torn when this happens.  When you lowered the engine and transmission by an inch, did you shorten the driveline?
108VanGuy...

I believe this was from a failed u-joint. part of the rear u-joint was still there but the driveshaft and yoke are still in indy. I had left 1" travel on the yoke and had an original rubber mount at the top with the single bolt threw the center so with the exception of the 1" drop, it was the same as original. I don't blame the hanger, not entirely anyways. this hanger only allowed about 1" swing either way so by limiting the swing, it transferred the force onto the tail housing bolts and the weak point was the very thin wall aluminum. the new hanger was cobbed together mounting on the bottom and a rubber mount installed. swinging became a huge issue and I installed a brace to the frame but constantly broke bolts. while adding 2 heavier braces and more bolts may of worked, it would basically be a crossmember at that point so I just ordered one for 60 bucks and made brackets to weld to frame.

Seth G wrote:What about a Holley 500 cfm 2300 2-barrel?

https://www.holley.com/products/fuel_systems/carburetors/performance_2_barrels/

Thanks Seth - didn't realise this was aimed at me, that looks like great value, even with new manifold or conversion plate kit!

or you could add 2 weber 2 barrels!

That's a sweet looking setup - but petrol is the equivalent of about $8 a gallon so it could get scary...

Fcat wrote:That's a sweet looking setup - but petrol is the equivalent of about $8 a gallon so it could get scary...

they claim 10 mpg better than stock but I have my doubts. I will know soon enough.

That's tidy - mine is a horror show in the Dog house!

Hey Scott
Nice looking spark plug wire retainers. Where did you get those?
108VanGuy...

for those still skeptical, the Clifford does fit in a first gen box (barely!)  

with only 1/4" clearance at the choke, I can either run a hand choke, lower the passenger side of crossmember with a couple washers or slightly bulge the doghouse. the bulge doesn't technically count as fitting in the stock doghouse but if done right, should look as if it was originally stamped that way.

I PUT A CARTER 400 FOUR BARREL ON CLIFFORD INTAKE WITH AS BIG AS CAM I COULD FIND THE HORSEPOWER ON THE 250 PUTS V 8S TO SHAME AND YOU DON'T HAVE MESS WITH YOUR FRONT END!! weight!!the Offy will have a flat spot (cold fuel) on take off from idle