New valves/ valve springs with new cam?

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74 dart sport

Kameron
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I currently have an RV cam (not sure of the specs) in a 318 from 1967. I am thinking about upgrading the cam to a summit racing cam (285 duration, .480 lift) or maybe something bigger than that. Would I need new valves or valve springs ( I think the current ones are stock)? Also, would anything have to be changed besides the valves? Thank you
 
go with new springs, and stay at around .480" lift so U do not need to cut the valve guides down for clearance. U do not need new valves
 
74 dart sport said:
What are retainers and locks? ( I haven't heard of these before)
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The retainers are the round thing on top of the spring. The lock is what sets inside the top of the retainer and locks it to the valve. That way the retainers are matched to the spring in case the diameter is a bit different than stock.

The stock ones that you have will work as long as they fit the spring.
 
Ok. Also, the cam I am looking at says a 2500+ stall converter is needed. I currently have a stock 1967 727 with a shift kit. Is a 2500 torque converter really necessary in this case?
 
74 dart sport said:
Ok. Also, the cam I am looking at says a 2500+ stall converter is needed. I currently have a stock 1967 727 with a shift kit. Is a 2500 torque converter really necessary in this case?
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Probably, or you won't get the performance you are expecting.

74 dart sport said:
https://m.summitracing.com/parts/sum-k50062 here's the link to the cam. It is made specifically for the car. Also, I looked under the suggested and required parts and did not find any spring sets. Any help ?
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That cam requires 9:1 compression. Probably a bit much for an otherwise stock 318, usually between 8 and 8.5:1 compression.

I think I would step down a notch.
 
Bad Sport said:
Probably, or you won't get the performance you are expecting.



That cam requires 9:1 compression. Probably a bit much for an otherwise stock 318, usually between 8 and 8.5:1 compression.

I think I would step down a notch.
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Right. Thank goodness you could help me out here. What would be the biggest you would go?
 
the 1967 318 is around 9:1 compression ratio. what is the entire combo - rear gear, carb, intake manifold, vehicle weight, exhaust, etc. and what are your goals and intended use. the 340 spring is a good upgrade for an early 318
 
There are a number of things to consider. What do you want just a nice street car?

Most cam upgrades are going to want at a minimum a rear gear change to take advantage of it. I run a Comp HE268H in my 318 (in a 74 Dart Sport). I also swapped out the rear to an 8 3/4 with a suregrip and 3:55's, it runs pretty good with the stock converter and those gears.


First things first, decide what you want. Street car that you can cruise on the highway too?
 
Rear gear: 2.76 but going up to 3.55s soon
4 barrel 600 cfm carb
Edelbrock intake
Weight- 3100 lbs
Exhaust- 3 inch headers to 2.5 at muffler (flowmaster super 40) to 2.25 ay tail pipe.

It's mostly a street car with a minimal amount of highway driving
 
Not to go jack your thread, but are you pretty happy with that 268 comp cam BadSport? That's what I'm leaning towards for my mild 360 going in a heavy 3/4 ton 4wd. Headers, port matched heads, 2.02 int valves,an old torker 340 intake, because it was new and free, a 600 quickfuel carb and 4.10 gears. Just want some mid range torque,decent idle and plenty of vacuum for power brakes
 
Dartish said:
Not to go jack your thread, but are you pretty happy with that 268 comp cam BadSport? That's what I'm leaning towards for my mild 360 going in a heavy 3/4 ton 4wd. Headers, port matched heads, 2.02 int valves,an old torker 340 intake, because it was new and free, a 600 quickfuel carb and 4.10 gears. Just want some mid range torque,decent idle and plenty of vacuum for power brakes
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Yeah, it's a good cam, but I would think you would want something that would be more of a stump puller in that 3/4 ton.
 
74 dart sport said:
Rear gear: 2.76 but going up to 3.55s soon
4 barrel 600 cfm carb
Edelbrock intake
Weight- 3100 lbs
Exhaust- 3 inch headers to 2.5 at muffler (flowmaster super 40) to 2.25 ay tail pipe.

It's mostly a street car with a minimal amount of highway driving
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Take a look at Hughes Whiplash cam.

Hughes Engines
 
Bad Sport said:
Take a look at Hughes Whiplash cam.

Hughes Engines
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I looked at those whiplash cams, sound pretty wicked. I can't believe a cam that sounds that evil can run with low compression and make the torque and vacuum on need. I know the torker intake seems to be out of place but I've ran them on stock chevys, a few mild molars and an old solid lifter 340. Never found them to be a problem unless you spend all your time on a dyno and look for that extra 3 or 4 go. The 4.10 hear helps and I've always got low in the transfer case if I need "diesel" torque.lol Just wondering if that 268 comp comes on pretty quick and idles fairly smooth. Those whiplash cams just sound wicked but I'm looking for something a little mellow sounding for the truck. I can get the comp stick and lifters for about the same price as the Hughes cam
 
RustyRatRod said:
The Summit 6901 would be a good choice.
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Specs look good but I'm staying away from the summit stuff. Not sure whose supplying their lifters but I've got a set that had 2 fail after couple thousand miles. Running 509" springs on Indy reman heads. Preload was dead on, spring installed height spot on, yet 2 lifters collapsed and started ticking at start up, now a buddies summit cam kit in a small block chevy lost one too using edelbrock springs in a very mild 327.
 
Dartish said:
Specs look good but I'm staying away from the summit stuff. Not sure whose supplying their lifters but I've got a set that had 2 fail after couple thousand miles. Running 509" springs on Indy reman heads. Preload was dead on, spring installed height spot on, yet 2 lifters collapsed and started ticking at start up, now a buddies summit cam kit in a small block chevy lost one too using edelbrock springs in a very mild 327.
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It wasn't the cam or lifters. Crane supplies all of Summit's cam stuff. It's high quality.
 
If I would have known that were made by crane, I would have went elsewhere. My first 340 I built with a mechanical cam had crane push rods, springs and retainers. After a dozen passes, I went to set the lash, several broken retainers, springs we're weak with a 500" cam. Put stock 273 push rods, Direct Connection springs and retainers on, many thousand miles later it still spins to 7500rpm without any problems. Some people get good results from crane stuff but I won't spend my hard earned money on it after experiencing those kind of failures in such short time
 
None of the cam manufacturers make there own stuff. They put their grinds on cam cores they buy from someone else (only two manufacturers for cam cores), and everything else is just reboxed parts. There are only two suppliers for lifters (Delphi, and someone else I can't remember right now) as well, so my suspicion would be dirt getting in the lifters caused them to collapse. Btw, Mopar Performance reboxes everything too.
 
Yah I found out about molars little reboxing gimmick after buying their Hv oil pump and seeing Mellings part number on it
 
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