153 Chevy Custom Header and Intake Manifold's

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Here by request is a thread about the intake and header i built at home for my Chevy 153 engine that was in my '47 CJ2A that is pictured in my avatar. I used my mock up engine, an OMC 153 as my jig to build them. The flanges were made from 1/4" cold rolled steel, i think it was 2 1/4" wide. I used a hole saw sized appropriately to make all the holes for the intake and exhaust. The intake started out as a piece of 2"or 2 1/4" exhaust tubing that i had bent into a 'U' shape at a muffler shop, then i cut it up to make it fit. The carb flange is just a piece of scrap flat steel plate i had laying around in the garage. The intake shown here was my first design, it worked ok, then i decided to build another intake later on that turned the carb 90 degrees from this shown position and it worked alot better. (i got this backwards in my reply on the thread titled '153 swap begins', sorry for the confusion, it's been a few years now) With the second design intake, the one side of the 2bbl carb fed the front two cylinders and the other side of the carb fed the back two cylinders. There was a common area under the carb so everything would 'balance'. It worked really well, the throttle response was night and day. As you can kind of see in the second picture the carb sits up a bit higher than normal for one of these engines so that acted like a ram effect, it was just as sensitive as fuel injection!
As for my header, it started life as a painted Hooker Hedder for 1963- 1981 Corvettes. I chose it because of the design, it was a long tube design, to have extra tubing just in case i changed my mind on the design later on. I took the sawzall and chop saw to it right away and soon wound up with a pile of pieces of tubing. Bolted the flange onto the head of my mock up engine and began the task of tacking all these pieces together. The collector was still a 3" that i positioned right in front of the stock CJ2A steering box as room is kinda tight underneath as we all know. I ran the front pipe down under the oil pan and down the passenger side. I have room on the passenger side as this Jeep is 2wd. Once everything was finished welded i sent to header out to get coated in a high temp coating.

The third picture is what the finished engine looked like. It's a early production 1962 Chevy II 153 that used to be a race car engine. It had alot of funky stuff done to it before i bought it. It had been bored out .040" already with an unknown camshaft. I wound up taking this engine out as it had a weird noise in it which we found, had a rebuild done, got a custom ground cam made for it with the same specs as a 327/350hp engine. Got this version running and oh baby was it ever wild running! I reffered to this engine as half a 327 because it basically was. This version didn't last long because the noise came back and upon tear down we found a crack in #4 cylinder and it literally 'ate' the camshaft. I found a bare block advertised quite aways north/west of me along with other parts for these engines. It turns out the seller and his brother bought a (at the time) very low mileage 1962 Chevy II with a 153 in it back in 1970 because they were gonna build a dragster with it. They also bought some speed aprts too, like a set of Jahn's Racing Pistons which were domed and a Chet Herbert Racing Camshaft, solid lifter with .640" of lift! This was going to be a really wild engine but they abandoned the project and it just sat until i found it. I bought everything the guy had and brought it all home in the back of my '97 TJ. 

I tore the old engine all apart and transferred it over to the low miler block, had the domed pistons put in it but not this cam, the machine shop suggested a certain Comp Cam for it so i bought that for it. I reused my header and second design intake. Only problem now as that i was stuck with running minumum 94 octane gas in it because it wound up having slightly over 11:1 compression. I ran this engine for awhile, it's not easy finding 94 octane gas around here and it's expensive, so the descion was made to take this little screaming gas miser out and in went a bone stock 4.3L Chevy V6 2 winters ago. 

One thing i found really cool/ neat about my last 153 was how it idled, you could almost hear each cylinder fire when it was idling, it sounded like a V8 going down the road, nothing like a wimpy rice burner 4 banger does. Like they say, theres not replacement for displacement! Just before i pulled this engine out i went into a gas station to fill it up. It was a full service one and the attendant was likely in his late '50's, he heard this thing idling away as i was waiting my turn to get to the pumps. I finally get up to the pumps and shut it off, then he asks me if the Jeep has a 427 in it! I said umm, no, it has a 4 cylinder in it i reply. He didn't believe me, so after i filled up the tank i openned the hood to show him, he couldn't believe a 4 cylinder could run that wild and sound like a big block! The force of the exhaust coming out of the tailpipe was wicked too, it would actually push your leg away.

I sold this engine to help finance my 4.3 swap, but i am thinking about getting another one, likely a 181 this time, besides, it's not like i can't build a header and intake for it right??

Edited by jeep4752 - 26 Dec. 2012 at 4:32pm