The Stovebolt Site Forums The Shop Area Engine Shop Egine Specs on GM 261, 270 and 302

I have an 87 Chevy Pick up 1/2 ton 4x4 in excellent condition with a 350 TBI. Runs great! I'm the second owner. Love this truck. I'm just not a 350 man. I love the old inline sixes. Leaves lots of room under the hood and have a nice purrr to them. Its only has 95k original miles with a 700R4 trans. Want to put in a stovebolt. Does anyone have a book that gives the specs on hp and torque at rated rpms and compressioin ratio? Will they bolt up to the trans? Did one Bolt conversion on a 80 Scout from a worn out diesel to a gas inline. It might be a one of a kind if I do this as far as I know. Started working on vehicles 40 years ago. Helped my Dad a few times before that. Just would like the specs if possible. Thanks. I am brand new at this site. I think its GREAT for like minded people to get together and share info and ideas and such! Henry

Hy Henry G, I think your swap to a six would be a lot easier if you used a 292, or the smaller brothers 250, or 230 if your interested let us know and we'll dig up some spec's

Thank you for the quick reply. The ole' 292 is a stump puller for sure. The smaller brothers are just as well built. Had owned all of them at one time or other. Always ran for me. Easy to work on. Perhaps with some headwork and a better manifold from Offy or Clifford and an Edelbrock 4bbl carb might be the ticket. That and some roller rockers would give some good drivability. Don't need a racing engine. I already have 3" Magnaflow exhaust. Do you know if anyone make a TBI for the inlines? I would probably go with a carb for now due to $$$. There is a person that works near here and has 76 chevy Pick up and it has a 250 with 384,000 miles on it and it still runs well. I would say thats really good engineering! H.

Unless you drive all the time in first gear on muddy back roads,you'll be disappointed by swapping out the 350 for a 292 6.The 292 will be hard pressed to match the power of the stock 350 V-8 even after installing a cam,headers and more carburation on the 6.
I used to have a small fleet of PU trucks for work,a few were 292 powered,the rest had 350's,all were 4 speeds.The 292's were slower at all speeds,got the same fuel mileage as the 350's and didn't last longer.
There's no replacement for displacement in heavy 4x4 trucks

Hey Fast Truck, Thanks for the info. Haven't done anything yet. Gives me something to ponder. The problem is that I put a new harmonic balancer on it a couple of weeks ago with a new double roller timing chain ( the old one was stretched ) and while in there a new water pump. I still have engine vibration. I think the crank may be out of round or tweaked by the original owner being he just drove it that way without realizing it. At normal speeds it is not noticed much. But when you get on it to pass or step on it to get on the freeway or going down a mt pass or even idleing if you rev it up some then its apparent somethings out of balance. There about the same labor changing just the crank as putting a new engine in. What about the newer 285hp 5.3L thats quite popular and gets good mileage? The newest version is 315hp and 338 on the torque. I can get one reasonable. $800-$1200 from a wrecking yard with a guarantee. Should bolt in and Painless may make a harness for it. Any opinion on this set up.

Your truck's vibration could be a cracked flexplate or torque convertor issue if an auto or a pressure plate out of balance if a stick,so check out everything before you suspect the engine is hosed.

Hey Fast Truck, Thanks for the advice. I will do just what you said. Probably next week I'll have the tranny pulled if need be and check out the flex plate. Otherwise this engine runs super quiet. Uses no oil and no valve train noise either. It would save me a bunch of $$$ I don't have to spend. It has a 700R4 trans with 3.73 gears. At least its not the early 700R4. I was told there are updates that can be done on it but with 95k the tranny shop didn't recommend anything being it would increase line pressure and seal pressure. When it gets overhauled some day down the road then I'll have it done. But I will get this checked next week somehow. I REALLY appreciate it very much for your help and I'll post what I found. H.

In my opinion the engines mentioned in your title are better for vehicles 1962 and older. It would cost a lot of money to install a heavier and less powerful engine in your newer truck. You would also have a heck of a time passing any type of emmisions testing.

It's a long shot but check your balancer and flexplate to make sure someone didn't use a 400 small block piece at either location. The 350 balancer will be round and smooth and the flexplate will not have a balance weight on it. Probably not it because this causes a vibration that is very distinct (shakes like hell).

400 SBC flex plate will not fit on a 87 TBI motor.TBI motor is a one piece rear main seal and a 400 was two piece rear main seal. The flex-plate maybe installed with the wrong bolts.

Hey Everyone, This info is great. I called a tranny friend and he's going to check it out the first of the week. I ordered a new Torque converter and I'll pick up a flex plate this afternoo. just in case. Its only $57. Cheap enough. The converter is about $115 or there about. Since it has 95k I'll have it replaced anyway then at least its new and should last a long time since I take care of my rigs. Can't wait to find out what is going on. One other thing, what about putting later Vortec Heads and an Airgap manifold. Should make it run better??? Can get them reasonable. About $125 for good used set then take them to the machine shop for $150 and have them gone through. Just a question and thought. Have to run on a quick electronic repair job sounth of here in Yreka Cal then back home. H.

I already have a brand new harmonic balancer from a speed shop and a cover from Summit Racing. Helped a little. At least I can see the timimg numbers. White letters on a black cover really stand out. Went to do a service call and had to climb Syskiyou Summit. A long hard climb pulss a couple a steep grades and got only just over 12mpg. With a 700R4 and 3.73 with 31" tires thats not very good. Its only rated 185hp and 285 on the torque. Wasn't until 1996 that they changed the computer system and got some real power out of them. Over 300! Still have the throttling problem when ideling. Just goes up and down all by itself. Haven't figured that one out yet. Maybe a worn distrtibutor??? Chain is a new double roller when the other things were done a few weeks ago. Seems like going in circles. Timing does seem to vary. I thought the chain would have stopped that. Time for an MSD Distributor or what? Could it be the TBI? All the plugs a new and are burning tan. None are black or oil fouled. Uses NO oil. H. ?????