Projects First rod in almost 20 years. 30 Chevy roadster.

Great score on the 261! That’s a great engine.

 

My Chevy is a 1931, but I think the 1930 has the same under hood dimensions. The 261 should fit in there ok except for the cross member is too wide for the space between the oil pan and the bell housing. A piece of 1/4" aluminum plate can be bolted into the cross member and the original cut out in the middle. Although the 261 won't make as much horsepower as the GMC 302 you talked about earlier, the GMC block was quite a bit longer and the firewall would need butchering and then the rear of the block would have been near the dashboard. The 261 should make 150 to 180 horsepower and it will move the lightweight 30 with no trouble, especially with a 5-speed.

I have a 1934 3-speed and a 39 rear axle, which would have Huck brakes, but I decided it was better to go with a 5-speed and I'm going to use a 72 Nova 8.5" rear axle. I am using a 51 1/2 ton front axle, which bolts right in and that gives me Bendix drums on the front. I had my 261 cam reground by Delta to their "Bulldog" grind, which is a 254/265 with 10.5 degree lobe separation and around .42 to .43" lift at the valves. For the intake I have a Harper non-progressive, but I also have Offenhauser 3 carb and an Edelbrock 2-carb in case things don't work out with the Harper.

Those original 194 engines have small valves and ports, along with a weak valve train. I also believe they only have 3 main bearings, but I've never opened up the bottom of one of my 194s. The 31s supposably had a little better cam and the 32 featured a downdraft manifold and carb. I guess you could have the cam reground, but you would still be limited on power and probably on reliability.

 

Mine, the plastic wrapped one, has the "captains bars" and is date coded 1958. I really wanted the insert style bearings and other upgrades after the issues I was having with my 194 last winter. I'm sure I'll have a whole new slew of challenges though!

I hear you in the 302 length, I was second highest bid on a 302 truck but I'm ok I missed it. I think the 31 is two inches longer overall, I just don't know where that two inches is.
I had a line on a 39 truck trans but I'm thinking the 5 speed and a rear axle swap is probably a better path for me. I ran the original motor around the block a couple of times, hopeful I could take my kids in the parade, but I had an issue with the front bearing that was going to take more work than I was willing to put into that motor due to it's limitations.

 

I did a little measuring on the 194 out of my 31 and of a 1954 235 that was handy. From the front of the bell housing to the center of the front motor mount, the 194 was 29.5 inches, while the 235 was 28.5 inches. That should mean you have the length for the 261. The 261 water pump and fan should be pretty close to the center of your radiator. I also measured what was supposed to be a 30 hood and a 31 hood. I measured them down the outside hinge, which probably isn't the best location and the 31 hood is 1.25" longer. However, I think the length difference in the cars is in the wheelbase.

 

I have a 270 GMC in my '53 Chevy pickup. I had to move my radiator forward about a couple of inches. But that is not an option for you if you are going to keep the hood & fenders stick. I believe the overall length of the 235-261 with the long water pump is very close to the GMC. The 235-261 & early GMC with front mount share the same front mount plate, timing cover, & timing gears. The GMC mount on the frame is 1 1/2" farther forward. Lots of transmissions will bolt right up to your '58. Pick any of the fun trannys you like.

I have one of the Harper non progressive manifolds mentioned above. The progressive is the same only with much more complicated linkage that requires splitting the throttle shaft on 3 two bbl carbs. It is the coolest carb set up for these sixes. The linkage is a work of art.
Keep us up on your progress. Chevy roadster guys need to stick together.

By the way I will be using a '49 pickup front axle with Huck brakes on my '26 roadster. These brakes are fine but more of a pain to adjust. I'm using them because my 19" wire spokes fit the drum.

 

Pulled the valve cover today and it's gonna need a complete rebuild. Time to start stripping things down and hoping for no cracks. Pretty sure a family of mice were living in there.

 

Unlike the 194 the parts are out there. You may want to really check and measure and get the parts together so you can bore & grind to fit what you find. Pistons will be the toughest but there are several sets on eBay.

 

My plan is to start with the head. I'm going to pull it this week and have it hot-tanked and checked for cracks. From what I've been reading I don't hold out much hope for this head. Now if I am lucky and it checks out I'll have it rebuilt. When looking for parts it seems most things like valves and springs are shared with the 235. Is there anything specific I should be tracking down? I know there is a 235 head that is a good swap but I'm hoping to be able to roll with what I have.

Thanks,
Matt

 

Some how the mouse got corn all the way to the top of the pistons. Hopefully at least the block is salvageable. Dropping the head off later this week at the machine shop.

 

I hope it is all OK. I got an Onan Generator for free once because it wouldn't turn over. Pulled the heads and found that ants had filled one cylinder with dry sand. No damage at all. I cleaned it out and ran it for years. I read that mice only need 1/4", I'd swear their skulls are bigger than that.

 

I've got a 848 head from a 235 for my 261. It has a slightly higher compression ratio, but probably the best head is the 1954 powerglide head as it had larger intake valves. I don't know of a source for those powerglide valves or I would have had them installed in my head. Don't try to install larger exhaust valves as they are already shrouded by the head wall and larger exhaust valves may actually hurt performance. You can have the head planed to increase compression, but you would probably need shorter push rods. You need to measure our spring height and shim to spec after having the valve work done and you ought to have hardened exhaust seats installed too. I'm thinking about new stiffer valve springs and new lifters for my 261. Does anyone have a suggestion?

On the head, I milled the valve pocket opening some and polished up the intake ports and the valve pockets. If you can, polish the inside corner from the intake port to the valve pocket. I tried but didn't achieve much there. That corner is the worst point for the intake air flow. Don't open up the intake ports of the head, as that just makes that corner sharper. If your rocker shafts are worn, you can replace those with new shafts and that will tighten up the top valve motion some. Check the valve ends and the ends of the rocker arms at the valves for wear. I ground mine down and then smoothed and polished them to make everything even and smooth. I may eventually have to change out the whole rocker assembly. Chevy small block exhaust valves are the same as the 235/261 exhaust valves and I purchased a set of 1.5" stainless exhaust valves from Speedway and installed those. I remember more than one badly burned exhaust valve on a 235 when I was a kid. Stainless and hardened exhaust valve seats should eliminate that.

 

Nice roadster.
I am glad you are going with an inline six. I like them. (I am thinking about removing the "L" and "S" keys from my computer. Yuk)

 

Do you have casting numbers for the best heads. I know where there is a lot if 216-235- maybe 261 parts headed for the scrapper.

 

Egge makes them I am running Egge pistons in both of my 261s. Any piston company will make them but they are not going to be cheap, but I would much regather pay more to a company I know like Ross then take take a chance on some fly by night company’s pistons off EBay or Amazon.

 

The ones I was looking at were forged TRW NOS. There are other known brands too. The issue is the proper oversize. You can buy Ross pistons on eBay.

 

I'll pay scrap value for a few 235 heads and the freight to ship them out. Plus a little kickback to boot. Reading the stories online I don't hold out much hope my 261 head is salvageable but I may get lucky...

 

I'll have to get there pretty quick. I'll start looking for numbers. They'll be on the Inliners International site.

 

The 261 heads are casting number 3703570 from 1954-1957 and 3836850 from 1956-1962. These heads might have a lower compression ratio than the heads from cars. The casting number 3835913 was used on 235s for trucks and stick shift cars from 1954-1955. The casting number 3836241 was used for powerglide and Corvette 235 engines from 1954-1955 and I believe these are the heads with the larger intake valves. Look for a 1954 head with that casting number. The casting number 3886848 was used on 235 engines from 1956-1962 and this is the head with a little bit higher compression ratio. That should be a pretty common head to find.

 

Thanks! I see if I'm too late.

 

Don't forget to place a 261 head gasket on a 235 head and after marking the locations, drill the "steam" holes in the heads where the cylinders join. These holes will need to be drilled at an angle back into the water passages. That will keep the water circulating at the top of the cylinders. A 261 head will already have the holes drilled at the factory.