The Stovebolt Site Forums The Parking Lot '60-'66 Trucks Original Engine?

Hello, I have a 1965 C-10 with LWB, Standard trim, 3 on the tree. Currently has a 250 engine. Is there any way to determine what original factory engine my truck came with? I assume it was the standard 230, but I would like to know for sure.

Thanks

Decode the engine. Your inline six will have a casting code near the dipstick. I’m fairly sure the 250ci wasn’t introduced until 1966. A 230 & 250 look the same externally, so you can check the top of the piston with a feeler through the spark plug hole. The engine will also have a serial number stamped on the pad next to the distributor.

Check the location of the lower radiator saddles. The inline six will have the lower saddles riveted to the lower flange of the crossmember. A V8 would have saddles riveted to the upper flange of the crossmember. An inline six would have a taller narrow radiator. The V8 used a wide but shorter radiator.

Thanks very much Lugnutz. I have attached pics of the numbers on my engine. Does it have a casting date of April 29, 1965?

Yes. 4/29/65. You likely have a 230ci unless you have tall side covers. The 292 has tall side covers and the PS engine perch would be between the fuel pump and distributor. See pic.

Wow that is great news! I will check the position of the engine perch. I have attached a couple of more pics of the engine, but they don't show the engine perch. I will have to take some of this it.

One question, the date of manufacture couldn't be 1975 could it? Because I was told that it had a non-original 250 from the seller ??

Yes, I suppose it could be a 1975 engine. I’m not sure when GM started using an integrated head on the 250ci, but it looks like yours isn’t an integrated head.
You have a ventilation hose from the valve cover to the air cleaner which wasn’t present on a 1965 230ci, so that would suggest a 1975 engine. Pull a spark plug and feel the top of the piston with a pick.

Your picture shows the perch is behind the fuel pump, so it’s not a 292ci.

I appreciate your help very much. What should I use to feel the top of the piston?

The previous owner said it had a 250 with an integrated head. I am a greenhorn, but I didn't think it had an integrated head either. I'm hoping it turns out to be a 230. If it is a 1975 vintage 250, I'm going to swap it out for a 230 or 292.

A long wire. I use a 10” pick. Hand turn the crank so the piston is close to the top of the stroke.

Well shucks. I can’t tell if it’s integrated or not. It might be.

Ok. So just by feel I will determine the shape of the surface of the piston. Is it pretty easy to tell?

The 250 piston has about a 1/4" deep dish across most of the top of the piston. The 230 has four shallow valve reliefs, since it's the same piston Chevy used on the 283 V8 engine. With a bright flashlight and a long screwdriver, it's pretty simple to tell the difference in the piston shape.
Jerry

Ok thanks Jerry. What do you think, do I have a 230 or 250 based on what you have seen so far?

Blasted computer- - - - -it eats a post occasionally! Unless you can decode the stamped number on the machined pad by the distributor, it will be hard to tell. Both 230 and 250 engines use the same block casting, and the cylinder heads are also the same. The reason for the dish-top pistons on the 250 is to keep the compression ratio the same on the larger engine. About one full ratio of compression increase can be had by installing flat-top pistons for a Chevy 307 V8. The bore size, compression height, wrist pin size, and weight of the 307 piston is the same as the 250 piston. With a slightly hotter camshaft and the compression increase, the 250 gets pretty perky!
Jerry

10-4 I'll see what the surface of the piston is like tomorrow

I found the casting number. It is a 250. I guess it is a 1975 vintage.

So I will be replacing with either a 230 or 292. Is there any way to tell what it came with originally?

Thanks again for your help Lugnutz and Hotrod

Forgot to attach this table...

If you have an integrated head, you could swap it out for a non-integrated head and script style valve cover. Nobody would know.

Here’s a pic of my non-integrated head intake and exhaust.

Watch this video I made. Start at the 50 second mark or watch the whole thing. VIDEO LINK

Interesting. Thanks. I would like to have a periodic correct engine so I'm going to look for a 230 or 292

The data plate on the left kick panel will list the original engine size.

ESum, greenhorn here, where exactly is the left kick panel?

Thanks

Kick panel is to the left of where the drivers feet go. Vertical panel from floorboards up to dash area. Sometimes there is a data plate on either left or right kick panel and sometimes a sticker on the inside of the glovebox door. Good luck.

Ok. I have found the left kick panel and have attached pic of it. I will check for other plates in the areas you mentioned.

Thanks

Well, that listed all the engine options but doesn’t help with what yours was born with.

It does show all of the available engines and that a 250 wasn’t stock in 1965.

I was able to check the surface of the piston and confirmed it is a 250. Thanks Lugnutz for those pics and your assistance.

That is correct, Phil

In 1965, the 230 engine was stock and the 292-6 and 283-8 were optional.

It looks like the 250 was not available in 1965.
1965 Chevrolet Trucks

What is the code stamped on the block at the rear of the distributor?

It is 348675. Per attached pic is it a 250

Just from the picture, the distributor and the air cleaner are not 1965 and you confirmed it by the engine number. Also your data sheet says "without integral intake manifold". It seems like that if it runs OK just drive it. In general a good 75 250 engine would have somewhat better performance than a 65 230. 90% of the people that look under the hood won't know or care what is anyway.
Fred

10-4 I'm going to see how it does. For a while anyway...

I just dawned on me that the position of the motor mounts indicate what the original motor was. Since a 292 would require modification, that tells me it came with a 230. Does that make sense?

Mounts can be changed, but would likely leave a telltale mark. Yes, a 230ci is likely correct. A 283ci would use the same engine perches as the 230ci but the radiator saddles would be located on the upper flange of the crossmember for a V8.

There's only one worse choice for an inluine six in early-1960's stovebolts than a 230, and thsat would be the 194 used un the Chevy II and a few other compact cars. No matter what engine the truck was born with, running a 250 is a far better choice. Whomever did the swap to a 250 sometime in the past did you a huge favor!
Jerry

Hotrod you are right about the 250. That is the kind of advice I was looking for. Most people can't tell the difference anyways. If the 250 performs well enough I'll stick with it. I can use the money for the engine swap on a new paint job!

Now that I've expressed that opinion, I must admit that I've got a hotrod buildup for a 230 engine in mind. It's not going into a stovebolt pickup, however. Many years ago a bolter who no longer posts here gave me a partially-complete Excalibur roadster project, if I'd just drive to central Pennsylvania and pick it up. I'm a sucker for freebies, so I did just that. I've got ideas of making a "sleeper" hot rod, one that uses the universal bell housing bolt pattern of the small block Chevy V8. That includes the Mercruiser 4 cylinder, all of the 3rd. generation inline sixes like the 194, 230, 250, and 292, a bunch of V6's, and all the V8's. On any particular day, I could be running anything from a 153 4 cylinder to a 454 V8!

The 230 I have in mind would have a destroked crankshaft, forged lightweight pistons, NASCAR H beam connecting rods, a roller cam, and 3 side draft Harley Davidson carburetors, and would run all day at 7K+ RPM. It should sound like a bumblebee on steroids! In that fiberglass Excalibur body, it should be a Corvette killer!
Jerry

Wow! Way off the scale for my very limited mechanical ability to understand!

Regarding something I can somewhat relate to, I checked horsepower for 230 vs. 250. At 3800 rpm, the 250 has 105 net HP. At 3600 (200 rpm less mind you), the 230 has 120 net HP. Makes me want to go ahead and swap for the 230!

I’ll chime in because I drive a 1963 C10 with a stock 230ci several times a week. No complaints about performance from me. I’ve driven it with the factory 3 on the tree and now with a 5 speed tranny. Plenty of power for a C10.

I had a 250 in my 1965 C10 and loved that engine too. It’s a coin toss.

Here’s a graph of what to expect from a 1965 230ci. Your 1975 250ci might perform better or worse depending on condition.

I think most folks feel comfortable getting the RPMs up to 3000 on the highway. The engine will do fine at higher RPMs but it gets noisy. More noisy than most folks feel comfortable with these days. Jerry will tell you the engine can take the higher RPMs but from personal experience, I prefer to keep the RPMs just under 3000 on the highway.

Those HP figures are comparing apples and oranges, since there was a change in how the horsepower was rated somewhere in the mid-1960's. The only way to get a realistic comparison would be to have identically set up engines side by side on a dyno. The old adage "There's no substitute for cubic inches" usually applies, unless one engine is designed for low end torque (the 250) and the other is intended to produce high HP at much higher RPM. Putting a set of 307 V8 flat top pistons and a RV-style camshaft in a 250 makes it run rings around a 230 in a truck. Getting radical with a 230 and building it to spin twice its designed RPM and stay together makes it really come alive. "Ya pays yer money and ya takes yer choice!"

I'm also in the process of hiding 260+ cubic inches and about 50 more HP inside an original-looking 216 engine block!
Jerry

10-4 the education continues...thanks guys

Keep in mind, too, if you decide to go the 292 route, you'll need a different mount for the passenger side. I thought you could just unbolt the one and slide it forward and bolt it back in. But there is special passenger side frame mount/perch for the 292. If you stick with the 250 and the upgrades Jerry mentioned, you'll be fine. When I bought my 292 the seller gave me the mount/perch as part of the purchase.