273 Conversion Questions?

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Creeden

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Hello FABO!
I have a question for all that have been through the trials.

I am converting my 273 2 barrel to a 273 HI PO specs or as close as I can. I picked up an OEM 4 barrel intake but would like suggestions on other parts?

I have looked at several cams, but which do I go with? For instance a Crane Cam #H-248-2, Dur. 248/260, .400/.427, Is as close to factory as I have found but they say it advised for 800-4,200 rpm, and 7.75-8.75 comp. for brute low end torque.

My intent is to get the engine to as close as possible to factory specs. 10.5:1 compression (premium gas), find an original Carter Carb (4295S) or go new with spacer to adjust for bore differences (as I have read on FABO)?

Thank you FABO this is a great resource and a ton of knowledgable members!

KC
 
Well you can always pick up a USED Edelbrock carb on your local Craigslist WHILE you continue to look for an original
 
How are you planning to get the compression? Tear it down and fit Commando pistons? The original Carter is a great running carb, and I see them on Ebay from time to time.

That cam would seem to have a very different profile. The original cam was more of a top-end deal. I couldn't find anything really close when I rebuilt my Commando back in the late 80s. I wound up with a Crower hydraulic. Duration 264º, lift .427. No longer made, of course. I want to go back to a solid stick someday. I think I'll have to get a custom grind.
 
From what I have read and found the Isky E4 grind is the closest solid cam to the factory 4bbl 273 cam. Lift is the same, but with a little more duration. Toolmanmike post about his Isky E4 in his 273.
 
ok, thank you all. I will have to go back through the post by ToolManMike. Thank you again.

KC
 
MVH, yes I would like to get the proper pistons as well, and EGGE I guess make them (cast). Any resource on a forged piston?
 
TRW made a hypereutetic .030-over piston back when I built mine, so that's what I used.

Tx to white lightning for the info on the Isky cam -- I'll file that for next time.
 
Creeden said:
MVH, yes I would like to get the proper pistons as well, and EGGE I guess make them (cast). Any resource on a forged piston?
Click to expand...

I don't think the Egge's make the same compression as the stock pistons. I did a side by side comparison of the Egge piston against an old TRW forged commando piston which is no longer made. The Egge had lower compression height and bigger valve reliefs. I think the TRW's were closer to the factory commando pistons.

I know toolmanmike had trouble getting compression with these pistons.

http://www.forabodiesonly.com/mopar/showpost.php?p=1969625909&postcount=44
 
The Isky E-4 is the closest I came up with also. Solid cams pull and rev faster than hydraulics. I would keep your solid set up if you can. Replace the valvesprings also to get the most out of your cam. Toolman and I have posted sound clips of a running E-4 273. If you are running pump gas I'd use readily available flat top 2 barrel pistons. Also get a quick curve distributor. Nothing runs as good as an original 273 AFB on one of these engines in relatively stock configuration...
 
I don't think you would have any trouble running pump gas on a motor with the Egge domed pistons. If you run a perma torque head gasket and don't mill any more than necessary to true everything up, you'll have trouble getting much over 9:1. I believe Toolman landed at 9.22:1 with .030 over pistons and after milling .030 off his heads.
 
Why stock spec? go with 9:1 CR & .450+ high lift cam, idle-5500 intake & 600-650 carb, stock cam & intake aren't that great.
 
I wanted to rebuild my 273 as close to stock specs without having to have parts specially made. The Isky E-4 cam is very close to the stock 4 barrel cam specs. It works well and has a slight chop at idle like the stock cam has. The Egge pistons gave me a 9.6/1 ratio after milling the heads .030 and using a thin head gasket. I am not a big fan of milling heads/intakes but my heads were 2 different part numbers so it really didn't matter. But now I have a pair of heads and a intake that will have to stay together as a set or there will be a mismatch. I wouldn't worry about building a 10.5/1 motor. The 9.6 compression is pump gas friendly. I would hate to see you build a true 10.5/1 motor and have to run $8 a gallon race gas so it wouldn't ping. You have the 4 barrel intake and you are looking for a carb. You will also need a dual point distributor and of course the dress up goodies, valve covers with the chrome breather and pcv cap, and the air cleaner. You're on the right track. Keep us informed with your progress and have fun. tmm
 
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