help this old man out here need opinions

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trudysduster

FABO Gold Member
FABO Gold Member
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Time has come to get started on these 2 cars. I cannot get started on my Duster till about the 1st week in March because when we repaint it, I cannot cover it for at least a month. so I am going to get started on the Dart first. maybe as early as next week. I have talked to Tyler to find out exactly what he wants out of it and he said he wants it to sound like my Duster. That changes things a little as I was just going to put a Comp. XE268 cam and a set of heads on it. We had planned on building the last 340 we have and putting it in but the 360 that I went through last year is doing great so we have decided to keep that in the car and build the top end some. I have the 509/292 in the Duster and I love it. I know some on here doesn't think it is a good choice but it is what it is. The 360 that is in there now is a stock engine. May have a towing cam in it now but it is pretty stock. I tore it down before I put it in the Dart last year and put rings and new rod and mains in it. I have a set of x heads I plan on having done and put on it. I am going to put a new distributor and a MSD box on it and a new cam. He wants this car to sound like the Duster. would a 508/292 MP purple cam be a good choice for this. If I do, would a stock bottom end work well with it. We just done the rearend and went with the true trac Detroit locker and 3.55 gears. It is a 4 speed and I plan on ordering 4 new B.F.Goodrich Radial T/A tires for it probably 245/60/15 on the rear. Maybe 235/60/15. This is going to be strickly a street machine but he wants it to sound mean. I would appreciate your guys input on this and help me spec this out for best results. I thought about going with an Erson or an Isky cam as that is what I ran back in the day in my Chevelle but I know things have changed in the last 40 years. So here is a chance to help an old man and a young gun out. Bill
 
That looks like it would work.

As far as lift duration and all that, I'm still a bit in the dark, lol.

Is Tyler running power brakes?
 
yes, that was another concern. enough vacuum. also I checked the K20-602-4 cam and it said I needed 9.5-1 comp. ratio for that cam. I think stock I am running 8.4-1. would putting the x heads on there raise the CR to 9.5-1. these things I don't know. hope someone else can answer these questions.
 
I don't think you will get 9.5 out of it with x heads if the pistons are stock.
I have a 72 340 with KB 243 pistons.
With un-cut x-heads I only have 8.98 static compression and 8.06 dynamic compression.
But with a Lunati thumper I have 160 psi of cranking compression.
 
so how big of a cam can I go with if I put the x heads on there with stock pistons. I really do not want to pull it apart to put bigger pistons in it right now. I have KB flat tops in the Duster. would the XE268 work ok with x heads and stock pistons.
 
can someone tell me how big of a cam I can go with here with stock pistons and a set of x heads in this 360 . thanks, Bill
 
Comp Thumper cam...Call Comp Cams they have a great tech. line.Tell them what you have and they will find the best cam for your needs.
 
the 508 mopar cam in a stock low compression 360 is not recommended. this cam needs 10 to 10.5:1 compression ratio. but... if you want a good sounding idle and good performance and still a purple shaft from chrysler, you could use the 284/484 cam. it likes more compression than stock, so mill the x-heads .060 in. dont forget to have the intake face milled too so the intake fits. this cam should be used with a 3500 stall converter to work right . the distributor should be run without the vaccuum advance and one mopar performance light spring should be used instead of the heaviest spring. keep the other spring intact (the lightest one stock). if you dont want to use a 3500 converter, you should use a smaller cam.
edit: just saw this is for a 4speed car and the 484 would be a good cam to use.
 

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