The Stovebolt Site Forums The Shop Area Engine Shop Is it a good idea to install an RV cam in a 292 or

Is it a good or bad idea to have a small rv cam put in a 292? I had an rv cam in my 250 and it is way over cammed. Has low power and chews up gas big time. I'm going to order a 292 sometime next week when my check comes in and just want to best set up for it. Is stock the way to go or a cam just above stock on a full size pick up? It will have propane 9:1 pistons added, headwork, balancing and maybe headers. Will install roller rockers after when extra $$ comes in for them.

Most cam makers will use the same spec's for the 250 or 292 so the RV cam will be a little better in the 292. Bigger cubic inches take bigger cams easyer so it shouldn't be quite so bad at idle. As far as fuel mileage, any thing to far from stock could hurt it a bit. If you are going all out with headers and new carb/intake, then a bigger cam should go with them. Save your money on roller rocker arms, you will see no advantage to them, they are for high lift cams with lots of valve spring pressure. Did you install screw in studs for the rocker arms in the head? You should if you are planning any hard driving or $300 worth of rocker arms.
Its really up to you and what you want, you can get as many opinions as you want, and they all will be different. Joe

PS, have you been to the Inliners.org site? go there and search for 292 hop up

I haven't purchased rollers yet but maybe I'll just forget them. I don't have a ton of money to spend. I think the money would be better spent on headers. I already have 3" Magnaflow on my truck with the long quiet muffler. As for carbs? Not sure which way to go. I had a 4 bbl on the 250, but the 700R4 shift cable was a problem to hook up along with the accelerator cable. Thats why I thought of the two single barrels as the linkage would be easy to put on. Its was over carbed with a 600 Holley which the shop recommended they had on one of their rigs. Then they realized theirs was switched to a 390 cfm. A BIG difference. I have been to the Inliners site recently and some time back I got a form to join their club which I probably will do. Nice site. Good info. After the sour experience with the rv cam on the 250 I am leary about going that way again. There were two cams lower they could have used. They went with a Comp 240 cam. Had almost .060 more lift than stock. It went flat immediately on the back cylinder on the intake lobe. I broke it in properly. I primed the oil with a drill and watched the oil flow through the valve cover before I started it. It took a few times before it started anyway. I ran it for 27 minutes at about 2000-2500 rpms. It idles poorly in gear and has low power as it can't burn the fuel fast enough. Far too much fuel even with the stock one barrel I have. Even going down the highway it runs so so though better than in town. I'm sure the 292 will be an improvement over the 250 being its going in a 4X4. Got good gears. 3.73s with OD. I still have a 4bbl intake but I actually sold it with the 250. I could retain it if I wanted too. Just a hassle with the cables I mentioned. No bracket available to hook them up. Thanks for the answer and suggestions. I'll make up my mind by Monday or Tuesday when I order the engine. Its going to cost about $2300 for it. I could get it stock with the propane pistons for just over $1350 without headwork, harmonic balancer, rv cam or flexplate plus shipping including core charge as I don't have one. Thats with a 7/70 warranty. Not too bad. I think the porting and polishing will help it breathe better expecially climbing passes. I just want it to run the best and as efficiently as possible.

This is just a small suggestion, but if I were you I would put the smallest cam in your engine that you can find due to you running propane. I built a stroked 350 which of course is a 383cu.incher for my 86 4x4 5 years ago. I have been using propane for almost 30 years now so I have tried a lot of combinations. I know my engine is a V8 but it pulls like an ox at low speed and highway speed, My gear ratio is 3.08 with a 4spd manual transmission.
I wanted the cam to have the shortest duration with the highest lift, because I wanted to cram as much fuel and air in there at low speeds as possible and I also wanted an early closing exhaust valve. No more than 34* of in. and ex. valve overlap. This will also give you a nice smooth idle. With a 6 cyl. I would go less.My cam has a 111* lobe separation angle and is a dual pattern. I have excellent torque and power from idle to 4000rpm but I very rarly take it past 3500. Good flowing intake,heads and exhaust also make a difference. Fuel mixture screw does not have to be any more than 1/2 way out. My compression is in the nieghborhood of 10 to 1 but with a small cam like this your Dynamic compression will most likely be higher than would be practical if you were using gasoline due to the higher octane rating of propane. Detonation has never been a problem. Mileage with propane will always be less than gas since it does not have as many BTUs as gas but I justify this because it is 1/2 the price.
The cam is the heart of your engine. With a full size truck and a 6 cylinder engine on propane, bigger is definately not better when it comes to the cam. "RV" cams are to vague. You really have to look at the numbers. Good luck.

Brian

Hey Brian's40, This is real good information for me. Just what I needed to hear. Initialy I will run it on gas and then maybe propane. The new hydrogen fuel cell trucks and cars coming out I think use rather high compression. I wonder if older rigs can be made to run on it with some tinkering? The problem is the cells are very pricey and where can you get the fuel? Perhaps someday in the near future something like this would be possible. In the mean time gas or propane will work just fine. I probably go with a stock cam and possibly putting in lump ports. It would increase the flow with going to larger valves or cam. Is this a good idea? Should I stay with standard exhaust valves or go with the next size up? I have 3" exhaust to run it through which is plenty. Should I use a one bbl carb or two singles or one small 4bbl? I mainly looking for economy but do need some power. The 292 was good on gas when hooked to highway gears otherwise thirsty like the one I had. I think mine had 4.11 gears. It ran real well and I loved that truck which I should have kept. It was a 63 3/4 ton full size. Had a 4 speed in it. I really do appreciate what you have shared. This helps out a bunch. Where I used to work we had a small fleet of Chevy and Ford vans all with 292 or 300 inline sixes. The company just had them converted to run on propane with no change to the engine. They ran pretty good with 8:1 but as you mentioned loss mileage. The power was ok but less than gas. Not too much less. The chevy lost only 1 mpg. From 14 to 13. I'm not sure about the Fords. Henry