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  #1  
Old 01-01-2002, 05:52 AM
David Thomson David Thomson is offline
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Question 273 street combo - Thoughts/Suggestions??

Hi All,

It's time to upgrade the 273 in my daily driver 4 door 1967 Valiant (Australian) any ideas?

I am looking at stock heads, 340 cam, M1 dual plane, 625 Carter AFB, Pacemaker tri-y headers (aussie brand).

This would be working with existing dual 2-inch exhaust, 904 TF (stock converter) and 3.23:1 open diff (7 1/4inch).

Do you think the difference in port size will hurt things too much with the M1 manifold, would I be better off with a Performer or something like that?

Will the diff survive?

Has anyone used a 340 cam in a 273 before?

Will it do low 15s?

Has anyone run a similar combo before? I just want a fun little street motor to bash around in while I plan (and save!!) for a turbocharged 6 cylinder hemi in a 2dr Valiant hardtop for strip duty...

David Thomson
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Old 01-01-2002, 06:08 AM
Fast One Fast One is offline
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Sounds ok to me.

Diff should be all right but if you can locate a Suregrip that would be nice, I'm using the Borg Warner diff at the moment with the Sure Grip center, swapped gears from a Cortina 3.70 ratio, 4 cylinder auto, had low miles, it was from a mid 70's car ( better quality steel then ), it's handled pretty much anything I've thrown at it so far but for drag strip action with soft tires etc don't think I would trust it, I have a Dana 60 lined up for that stuff.

Engine is a 360 with Mopar 292 cam & all the other goodies.
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Old 01-01-2002, 06:28 AM
David Thomson David Thomson is offline
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Thanks for your input Fast One...

I can't wait to get the VE back on the road : )

What sort of Val are you running the 360 in?

Is it correct that the Borg Warner diff started with the VH in '72?

I here they are a bit wider than the 7 1/4 in the early models, but that the Borg Warner from the Centura is a good fit.

I will change the diff to a Borg Warner eventually but I will wait until I collect parts for the front end so I can change to the later 'ford' stud pattern.

Apparantly the 4 cylinder Pintaras cam with a 3.9:1 ratio in the borg warner. Just need a 5 speed behind the 273 so I can drop the revs on the highway : )

David Thomson
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Old 01-01-2002, 08:19 AM
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Christopher Christopher is offline
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For what it's worth...I used the 340 cam in a 318 with a 600 holley and Holley 4bbl intake.This and the small tube headers REALLY woke up my 318. I was using 2.76 gears in the 7 1/4 rear and they held up fine,although I did worry about them a bunch.My car ran 15.20 with the 2.76 gears and went 14.30's with 3.91's
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Old 01-01-2002, 08:43 AM
Fast One Fast One is offline
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Dave, yep the VH on is a different width I do believe, have heard of the Centura swap but not done it meself with other early Mopars I've had.

Can get Borg Warner gears up to 4.11 ratio from wreckers, think there is a company in Melbourne that makes new gear sets for them now as well but with straighter cut gears for performance use.

My current pride & joy is a 1973 Chrysler by Chrysler C.J. , I've taken all the luxury junk out which has lightened it quite a bit, I was using a Comp Cam 255 @ 0.050 , .590 lift mechanical, had a 292 Mopar cam doing nothing so thought I would give it a try to see the difference between the 2, the mechanical cam was a lot more dynamic so to speak & I miss it, so I'm going to put it back in, sounds nice with my gear drive too !!

I've played with a few 273-318 heads, best I've got was 411 HP of flow ( 200 cfm ) using Hemi 265 intake valves ( 1.94 ) but you might have valve to bore clearance problems with that idea on the 273, just for fun I hogged them right out & got 452 HP of flow then hit water !! They were pretty thin & definitely wouldn't recommend it.

Could bolt on a set of 360 heads with 1.88 intake / 1.60 exhaust, might need a notch in your bore though for valve clearance, easy to check out, different cc's too so machining for more compression is needed, air speed in heads should still be ok for the little 273 as long as the 1.88 valve is used & minor clean up of bowls is all that's required with that combo, just an idea I thought I would toss at ya.

Could put a 318 in ... plenty of them around, or even a 360, heh, heh.
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Old 01-02-2002, 10:16 AM
CudaMike CudaMike is offline
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Question

Fast One, a few questions. How much porting did you have to do to get 200 cfm out of the 318 heads? Share a few details if you don't mind. Also, I think I ask you a few months back about the 302 casting swirl port 318 heads, and you said you haven't worked with them. If you ever do please share the results.
Also, I was looking on a website about the Pacemaker tri-y headers and they look really nice. BUT, I presume they wouldn't fit US Mopars since your Mopars have right-hand steering, correct or no?
Thanks a bunch.
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Old 01-02-2002, 06:31 PM
Fast One Fast One is offline
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Hi Mike, I'm actually using Pacemakers meself & they fit without touching anything, isn't that a miracle !! Unfortunately they are for our right hand drive & would say not a possible swap for U.S. vehicles ( I think ??? )

I still haven't got around to playing with some 302 heads yet, I get pretty involved with our local stuff but hope to get a set sometime in the future, when it happens I'll certainly keep you informed.

I haven't done any 318 heads for quite some time now & the details are rather scratchy, cc's etc, but getting the 411 HP of flow out the 318 heads wasn't too much drama & safe eg, no water !! Still a lot of porting time though, probably easier just putting some 360 heads on with a minor clean up & machining to bring comp up.
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Old 01-02-2002, 07:36 PM
Sean C Sean C is offline
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For the 273 I would recommend the Edelbrock Performer over the M-1, because the runners match up with the performer, the 273/318 have small runners and the M-1 will overlap the small 273/318 runners.

It's okay to have smaller runners on the manifold , but detremental to have a manifold with runners that overlap the smaller 273/318 runners. Might cause a leak or at best does not provide a smooth flow for the incoming mixture.
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