Combination for a peppy 340

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FlamesAreWicked

FlamesAreWicked

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Some may know I picked up a 71 340 for my 68 Dart. It’s at the engine shop to be gone through. While trying to avoid the snowball effect I’m looking at some parts I may upgrade to “while I’m at it”. It’s a slippery slope. It currently has 587 J heads and I measured it having 2.02 intake valves. It’s .030 with silvolite 68-72 pistons. Also roughly measured it having a .484 lift cam. Talking about it with the engine guy, if I keep the stock heads, I could, if not definitely, be looking at some cost to refresh them. It got me thinking that it would be an opportunity (or excuse lol) to step up to the Edelbrock 60175 340 heads. They’re 65cc and made for a hydraulic roller cam. Also I was looking at a Howards hydraulic roller cam.. there’s two I’ve been looking at. I have 3.55 gear and a 4spd. Rpm air gap intake will be used and a Holley 670 avenger carb. Doug’s headers will also be used.

First one is .235/.243 @ .050 with .530/.530 lift on a 109, 2000-5700 rpm range

Second one is .243/.251 @ .050 with a .530/.515 lift on a 109, 2400-6000 rpm range

I think the little difference between the two comes down to the rpm range you prefer.. the first one being more ideal overall. 340s can spin but I’m not much of a track goer anymore.

Intended use is a fun street car. I live out in the boondocks so any sort of city driving will be in podunk towns around here. Car shows, cars n coffee, and cruise nights sprinkled in there.

I plan to use morel roller lifters as I think it’s basically what Hughes sells and they look the same as what Howard’s uses.. anyone know from experience if they’re the same? Or just buy the morel ones specifically?.. the carb will be a little small for optimum potential but I have it and I thought I’d use it. Ought to be a world of difference from the stock 318 and BBD setup lol

TF heads are the ones to have but they are more expensive and I wouldn’t be utilizing their full potential anyhow. If ever it sees the strip, it’ll be just to see what it can do for shiz and giggles. Anyhow, I look forward to having in the car by the time the Louisiana blaze has given us a break for the year.
 
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About that high :rofl:

Yeah I’ll need to get some measurements done.
 
That’s why you check.
“By the math”, the current Silvolite 340 piston would only stick out .005”.

Looks like you’ll be opting for the open chamber head.
 
Call Bullet cams and see what they can grind for you so you don't have to settle for too big or too little. You can get the Morel hydro roller lifters from Bullet already checked, cleaned and squeezed. Be sure to ask if they can grind you a roller cam on an LA blank instead of a Magnum blank. I had mine ground for my 273 during Covid and all they had was Magnum blanks. I had to run one of those Mickey Mouse cam snout extender kits from Hughes to be able to use a mechanical fuel pump. Nobody here who had the snout extender prior to my using it said they'd had a problem with it, so I sent it. Get the Morel lifters and have your machinist closely check the lifter bore clearances. If they are worn too much, have the bores bushed. You don't want rollers to have excessive wiggle room. Good luck with your build.

:thumbsup:
 

RustyRatRod said:
Build it stone stock with the four speed cam and headers. Done.
Click to expand...
I'm with Rusty, pistons are sitting proud of the block a fair way. Measure accurately to determine static comp, then do the math to work out dynamic comp using a cast open chamber head. Should be around 9.5 - 10:1 static, with 8:1 dynamic comp, that will work great with the MP 484 cam and pump gas. Run a set of long tube headers and have tons of fun!
 
I would run a step smaller cam than either of those.
Measure everything to make sure you will have good compression.
 
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Put it back together with a fresh hone, ring and bearing job.

284/484/108 cam, is that the old MP one?

those 2 other cams in OP need gear and converter.
 
I use TFs with the howards roller 1 step under those (on a 318 though) on 109 also... i am pretty happy with it.. sounds nasty and runs good.. shakes a lot at idle in gear which wouldn't be a problem for you cause of the stick though :) at stop lights my whole car shakes with it though which is getting annoying. (solid drivers mount not helping)

This is the cam i put in..

Hydraulic Roller Rattler Camshaft; 1964 - 2003 Chrysler 273, 340, 360 1800 to 5500 Howards Cams 718005-09 | Howards Cams

www.howardscams.com www.howardscams.com

This is through full exhaust (first time the car had moved in 49 years.. it was a mess)


P.S. if i could go back.. i would 100% go solid roller though... was silly not to start with one.
 
Be prepared to do some drilling and tapping on the SA670 to properly tune it. I put one on my 340 and it was waaay off out of the box. It's not the best choice for a hotrod motor in my opinion.

Though it's just a hydraulic flat tappet deal, here's the cam I run in my 9.7:1 340. It seems to run pretty well. For reference, my pistons were out .013" and the heads are 65cc if I recall.

Of your two choices, I'd go for the smaller one personally.

1756473201823.png
 
"Intended use is a fun street car."
You'd probably be happy with the .484 cam, stock valve size 587 (open chamber) & some simple port cleanup and bowl work. Using all the other things (Eddy heads & Hydraulic roller cam options) and a Holley 670 avenger carb is going to choke off all the money you spent. Sounds to me like you want a <6K RPM 340 that sounds and runs good. You'll get there with my first sentence and save several thousand dollars. Just have your machinist check the lifter bores and lifters for correct facing, break in the cam like you're supposed to and use a good molly paste on the cam and you should be fine, especially with the spring pressure (or lack of) required to run this cam. People love to spend other people's money when you ask for advice. Just my .02 worth.
 
does it need rebuilt or can you get away with a hone and re-ring and bearings? if that's the case i'd go in that direction.

if the heads need more than 1K worth of work, upgrade to aluminum.

that 484 cam is likely an MP purple shaft 484/284 stick which should be plenty "peppy". hell, i'd recommend something even smaller for what you're describing use wise. a stock 68 4spd cam or one of howard's street force series would work great. the two cams you listed are pretty aggressive and skew a little more strip than street, but you could get away with them because you've got some gear and a 4spd. but neither of them is really gonna make any power down low and if you don't have the compression to back it up, they'll be lazy.
 
RustyRatRod said:
Perfect for a stock four speed cam. Oregon Cam Grinders has the file in stock.
Click to expand...
Thats fine for a street cruiser. I'm running the Oregon cams '68 4 speed stock 340 cam with 9.75:1 compression, Eddy intake and AVS 650 carb. I have stock O heads cc'd at 63cc as they have 11/32 nailhead valves and a light mill. I've just had a few test drives but so far so good.

ps 3.55 4 speed
 
1MeanA said:
Thats fine for a street cruiser. I'm running the Oregon cams '68 4 speed stock 340 cam with 9.75:1 compression, Eddy intake and AVS 650 carb. I have stock O heads cc'd at 63cc as they have 11/32 nailhead valves and a light mill. I've just had a few test drives but so far so good.

ps 3.55 4 speed
Click to expand...
Trust me, that thing will melt the tires on command when you get it all worked in and tuned.
 
mopowers said:
Be prepared to do some drilling and tapping on the SA670 to properly tune it. I put one on my 340 and it was waaay off out of the box. It's not the best choice for a hotrod motor in my opinion.

Though it's just a hydraulic flat tappet deal, here's the cam I run in my 9.7:1 340. It seems to run pretty well. For reference, my pistons were out .013" and the heads are 65cc if I recall.

Of your two choices, I'd go for the smaller one personally.

View attachment 1716447987
Click to expand...

I bought the carburetor from a close friend of mine with intent of putting it on the 318, which would have been fine. The 670 would be so the “new” engine could be in a running and driving state. It’ll definitely need more.
 
junkyardhero said:
does it need rebuilt or can you get away with a hone and re-ring and bearings? if that's the case i'd go in that direction.

if the heads need more than 1K worth of work, upgrade to aluminum.

that 484 cam is likely an MP purple shaft 484/284 stick which should be plenty "peppy". hell, i'd recommend something even smaller for what you're describing use wise. a stock 68 4spd cam or one of howard's street force series would work great. the two cams you listed are pretty aggressive and skew a little more strip than street, but you could get away with them because you've got some gear and a 4spd. but neither of them is really gonna make any power down low and if you don't have the compression to back it up, they'll be lazy.
Click to expand...
Hoping that’s all of needs.. rings, bearings, polish the crank.. but if it needs more than a hone, I’d put some .040 over KB pistons in it. It should have a healthy level of compression while running in 93.
 
When it comes to wants and needs.. the lines can be blurred quickly. I’m sure the stock 68 340 4spd cam is a great piece. I don’t have any interest in using one.

People do indeed love to spend your money for you.. and this isn’t exclusive to the car community. A fun street car can be interpreted many ways. It can vary person to person considerably. Some people’s idea of a fun street car is a 800hp+ late model mustang/challenger/camaro. Other people may see a 140hp Miata as one.. neither route is wrong..

When I used to be up to my eye balls in guitars and amps.. people would talk about buying the nicest of custom shop guitars priced in $8k-10k range and beyond and own several. $10k guitar amp that would be loud enough for the stage at Woodstock and have a wall of them. Yet they played in their garage or basement. They’re not in a band and they don’t get paid to play.

While I won’t be living at the track with this thing, it will get used for more than idling through the local cars and coffee meet. It won’t be as egregious a Lambo owner who only takes their car out to the local starbucks 2-3 times a year but I digress

Guess we’ll just see how this combo works.
 
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