273 Supercharged...ITS HAPPENING PEOPLE!!

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UPDATE!! The Dream is not dead! Its been a long year at the Machine shop/engine guy. We have been plugging along slowly and as of THIS Thursday I will have a short block to assemble. You know how when you touch one thing you affect something else. Well that is amplified when there are not a ton of aftermarket parts to just pluck off a shelf to throw in. Lets rundown where we are right now.

Block was sonic checked and bored in three steps out .088, Surprisingly the walls on my 273 Block were pretty thick. I cant remember the thickness off hand but he made the comment that the walls after the bore where thicker than some of the 408 magnum stuff he does. So with the stock stroke the CI will land roughly at 287CI or 4.7L

We had to have a set of JE Forged aluminum pistons built for this bore and then a custom set of total seal rings. They look sweet. Once i get everything home I will take some pictures.

Crank is the stock forged Mopar crank. It was gone over and balanced.

Scat I beam steel rods. They are proven to 700hp stayed with steel just for the cost.

We are selecting cam Thursday..will be a roller just not sure spec yet.

Also making a final decision on heads. Now that the bore is opened up a small amount we are thinking i could get a slightly larger valve. So if that is the case might be looking at getting a new set. Also will be selecting the rocker set up. Probably will stay with the shaft style and roller tip.

The plan as it stands right now is to yank the /6 and 904 and get the new motor trans (built 727) and rear (8.75)in the car, running and driving by next spring. So I will have a hella built low compression 287. But I can work on getting the turbo stuff together and attack that the following winter.
 
Looks like a fun project! Bottom end is nice and strong. Two 58mm turbos seem big for a 273. I run a single 62 mm turbo on a mag 318 and get into boost at 2500 and limit it to 13 lbs.
 
Well if the block is thick,and you have a factory forged crank plus good rods hell push the thing and see what it'll take! I know the factory 440 forged cranks routinely withstood 700 h.p,not sure what a small block crank will take.
 
needsaresto said:
Well if the block is thick,and you have a factory forged crank plus good rods hell push the thing and see what it'll take! I know the factory 440 forged cranks routinely withstood 700 h.p,not sure what a small block crank will take.
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I've heard several builders say 575-600 is where they would push a SB but it's all relative (parts, machining, etc). If we start talking R-series blocks and serious internals then the 700 range is doable.

Btw: Great project! I commend you.
 
Update!!

Short block has been assembled! After a long dead end search for a tapered ring compressor small enough for this tiny little 3.7 bore I ended up having to use the cheap sheet metal style. It worked ok so we are on to bigger better things!! Chris @ Pie Performance has been a huge help. Answered some silly questions I had having never built a Mopar.... I only had to take out the pistons once after installing them due to my lack of understanding of spiral lock wrist pin retainers. I had never used spiral locks and didn't install two per side of the wrist pin and ended up with a ton left over. So all in all it went together great. Chris Stopped over last night and measured the piston depth in the block so he can finish up the machine work on the new heads. We ended up having to stay with the smaller valves to clear the block but the heads will flow a ton more than the stockers! Once he finishes them hopefully this week we can install and double check clearance. Hes going to help me degree the cam in and I should be finishing the long block this weekend. last piece of the puzzle is the push rods. once heads are installed we can measure them out and get them coming. Im going to run this bad *** edelbrock Super victor intake. 1. It looks super bad ***, 2. It has injector bungs all set up in it. so its easy to switch over to injection once i get that far!

Thanks for keeping up if you are and I hope to add more pictures soon! I believe Chris signed on as an advertiser on FABO so please check him out!! Performance Injection Equipment.

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I'm assuming from the pics You're using 318 Magnum heads, which size is the "smaller" You refer to valve-wise? Also, the intake looks like std. LA bolts, not the vertical Mag
style, is Your machinist planning to drill/mod that?
Project looks great coming along, glad You've got a nice building block together!
 
Update!!!! Still poking along in between Gymnastics meets and a business to run. Finally got the thing painted and more parts ordered. I have the Transmission now and I am picking up the converter soon so I don't have any specs on that. I know everyone has a preference on the color of this motor and I was so torn..... I think this fits. It is after all only a 273...right?? I am really trying to get everything ready so that when I am ready to do the switch it is mostly all here. There are so many small things that I know will hang me up. Anyway the dream is not dead...more pics to come as I get this big Jegs order!!
Killer6 said:
I'm assuming from the pics You're using 318 Magnum heads, which size is the "smaller" You refer to valve-wise? Also, the intake looks like std. LA bolts, not the vertical Mag
style, is Your machinist planning to drill/mod that?
Project looks great coming along, glad You've got a nice building block together!
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Sorry its been so long since I have been on. The heads are like a hybrid of a LA bolt pattern with magnum valve covers and standard LA intake I believe. I am not 100% how all this goes together just yet but I have had a standard Edelbrock LA intake sitting on it with most of the bolts in. Thanks!!
 
chrissock said:
Update!!!! Still poking along in between Gymnastics meets and a business to run. Finally got the thing painted and more parts ordered. I have the Transmission now and I am picking up the converter soon so I don't have any specs on that. I know everyone has a preference on the color of this motor and I was so torn..... I think this fits. It is after all only a 273...right?? I am really trying to get everything ready so that when I am ready to do the switch it is mostly all here. There are so many small things that I know will hang me up. Anyway the dream is not dead...more pics to come as I get this big Jegs order!!



Sorry its been so long since I have been on. The heads are like a hybrid of a LA bolt pattern with magnum valve covers and standard LA intake I believe. I am not 100% how all this goes together just yet but I have had a standard Edelbrock LA intake sitting on it with most of the bolts in. Thanks!!
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Hm. Was there supposed to be a pic of the painted engine attached to this? *eager*
 
Yea so pictures didn't work. Lets try again.

I ordered these sweet Magnum black Valve covers from Jeg's and they don't fit worth a crap....PRW is who makes them. I guess I will have to send them on back and try something else. Any recommendations for a cool fabricated aluminum valve cover for a magnum?

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I have LA Mopar Performance valve covers on my mag heads, they clear the roller rockers with 2 gaskets.
I only used 5 studs and nuts to hold them on but no leaks.
 
Slowly creeping up on this thing. Engine is done. Its at the shop getting the freaking Intake milled to fit since we messed with the deck height. Then it will go on the engine dyno and get broke in and run. once I get it back I am ready to get the swapping!! been busy getting the rest of the components ready. Trans is painted and some of the smaller components have been added like the speedo gear. and the Rear I tore apart and found some small issues so its getting new green bearings and some new brakes and Paint. I have hopes of getting all this started later in October. Man what a journey!!
 
needsaresto said:
Journey indeed!Congrats on your perseverance.
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Man when I get this thing on the road its going to feel so freaking good. Been a fun time though. My first real build from start to finish. And for sure the farthest i have ever ventured into a build. Really cool learning though. Here are some pictures to show more progress.

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More Pics. Had to move the spring perches. So I bumped them over another 1/2 inch so I could squeeze the most i could out of the rear tire area. Ordered a shackle kit from Dr. Diff.

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Any plans to mini tub? You might need even more tire.Turbo's produce prodigious amounts of torque and horsepower,but the launch of the car isn't as hard as a big block. But get it up in the mid range and your car may end up facing a wall mid track without enough traction.
 
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