The Stovebolt Site Forums The Shop Area Engine Shop Second 292 engine build - need tips

OK guys. As many of you long time bolters remember I got the first 292 done a couple of years ago. Learned some valuable lessons from that first build. The most valuable of all - spend the extra few bucks and use hardened exhaust valve seats. :rolleyes:

Anyway now that both my boys are big enough to get into other things and not have daddy watch them every minute I'm pondering my next project. I want to build another mild 292 but I want to get as much torque out of the engine (naturally aspirated) as possible. I want low end torque like crazy this time. Here are the parts I currently have to work with.

1. I have both the Clifford water heated single 4 barrel intake and the Offenhauser single 4 barrel intake (which of course I'll fab a water plate for, for street use).

2. Clifford shorty headers. I'll probably get a set of Stovebolts if I go with the Offy intake.

3. 2 sets of 292 LPG pistons - one is .030 over and the other .040 over. These bump the compression ratio up to around 9-to-1.

4. Brand new GM HEI distributor.

Here are the parts I'm considering buying and work I'm considering doing or having done.

1. Mild Schneider cam with a high lift and single pattern grind.

2. Really good port and polish of the head with slightly larger intake valves and stock sized exhaust.

3. Stock rods and crank, all reworked and balanced, using a 2 groove GM factory harmonic balancer.

Any suggestions for additional work or changes to my current plans are welcome. I'm building this for a street cruiser, as the vehicle it will go in will probably be geared to turn around 2100 rpms at 70 mph in top gear. I'm hoping to get 350 true lb/ft of torque out of this engine. Horsepower is somewhat irrelevent. Let me know what you guys think! TIA

-ftyler

Sounds real good.
I have a similar set-up. 292 L6 in '68 C/10 stepside. Original truck's engine, bored .030, Badger pistons, Crane cam --260, Rhoads lifters, Intake valves for a 307: 1.84, Clifford headers, Offy intake (unheated --I live in Tucson), Edelbrock 1404 [500 CFM] replaces the 27 Y.O. Holley 390. Currently debugging the AFB. . .

BT-K750,

Do you have the LPG pistons? How does your perform on the low end? Is there anything you would do differently next time?

-ftyler

sorry to hijack what mpg do ya get with a 292?

Best way to get brutal low and midrange power is cubic inches.Graft two inlines 6's side by side,engineer a coupling drive for the two engines.Now you got 600 cubes to play with.

ftyler: It's my 2nd 292 build up too. But it took me 25 years to get around to it and almost 3 years to complete. [First one went together in a summer in '77]
Badger pistons were cast. I found out that forged pistons are now real hard to find. They are not the LPG ones.
BTW, the Offy intake is supposed to be better for low end torque, while the Clifford intake is supposed to be better for higher end RPMs.
Regrets? Well my machinist freaked when I told him I had put in Rhoads lifters. I thought the cam was going to be lumpier than it is. He didn't think I needed them. (or the expense)
Also I'm running the hi-volume oil pump. Larry Page, "Twisted6" on the Inliner forum, told me he had no problem with the faster pump on a street machine, but the concensus is that you don't need more than the regular oil pump or you run the risk of sucking up all the oil from your oilpan and running dry. 6 Quarts in a 292? -- that's gonna take some doing. But even Santucci recommends the standard volume oil pump.
The 292 L6 has a lot of grunt on the low end.
Right now -- about 600 miles into break-in -- I'm still using points, but I have a fresh Accel blueprinted distributer I'm going to rig with Pertronix Ignitor II.

Chevy283: Mileage should be about 12 MPG, but it's about 6 right now -- which has me working on some break-in/tuning issues.

FastTruck: Somebody on the Inliner forum has a dragster with 2 292s inLine, one each fore and aft.

The 302 GMC I just built has what I consider exceptional throttle response and a lot of power from 1000-4000 rpm.Don't know if a comparison of the two engines is fair,but the 292 is similar to the 302 if nothing else,although the 292 has a longer stroke and smaller bore and a different combustion chamber design..
I went with 9.25 actual measured compression using custom forged pistons,compression always builds power to a point if the pistons are flat top or slight domes.
I had a cam ground,215 degrees duration at .050 lift,total lift at the valve is .430 with fastest lift possible and still retaining reliability.I degreed the cam to open the intake .050 lift at TDC and closing is 35 degrees at .050.These specs were the limits on a reground cam,292 cams can be made with more lift.
The engine has a Holley 390 cfm 4 bbl on a small runner Patrick's intake,the secondaries of the carb open as late as possible.
The head has larger small block Chevy valves,but no real porting other than blending in the new valve seats, minor port matching.It's important not to go overboard on home brewed porting.
Home made short tube headers into a 3 inch single pipe and a 3 inch Flowmaster Big Block muffler.
The distributer was recurved for 12 degrees initial advance,34 degrees total at around 3200 rpm,a vacuum advance is used,limited to 2/3 of it's original advance.
The engine idles at 750 rpm with a slight lope and will run on 91 octane pump gas but does detonate slightly at wide open throttle,93 octane is readily available here so that's what I use.Power is everywhere in the RPM range,falls off above 4500 rpm,which is just fine with me.
I very pleased with the results and I'm no pro engine builder,just used what works.
Best advise is to think about what you're doing and try to ignore the traditional tips offered by many Inliners guys.I was told this engine would have too much compression and cam for the best low and midrange power,not true.

The June edition of Hot Rod magazine has an article on building a 292. I haven't read it yet but just got the info on old chevy trucks online this morning. I built the 292 I'm running in 1970 3/4 ton 4x4 surburban that I use for hunting and to pull a stock trailer. I learned the hard way about hardened valve seats. Crane High torque RV cam with HEI ignition from a 78 250 gives more than enough torque and now I'm more concerned about MPG. Jim

According to that Hot Rod article, 283 pistons will work in a 292. Ftyler, you might want to find a copy, it has some very interesting info.

Guys who actually build 292's say small block pistons won't work,the distance from the piston pin to the piston top is different.That's why performance pistons for 292's are expensive,correct?
So someone is wrong here.There is so much BS about building inline engines.

I got started with 292's after reading an article about them in 4X4 magazine written by Clifford performance. They had all the info then and they are a reliable source. I followed their plan for a basic engine build and it turned just as they said it would. Jim

Whoops, my bad...283 pistons work in a 230.

Besides the fact that it was free and in good shape, I'm going with the 250 for the greater parts interchange.