Whats needed to fit roller cam into my 1971 340?

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Nidhögg

Nidhögg

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Hey!
This is not really due anytime soon, but I will hopefully complete my Dodge Dart 1968 with an 1971 340 engine this winter (had a new child so my time-frame got seriously kicked to the curbs :D)
Anyway, this is the high comp engine (10.5:1 if I remember correctly), with 2.02" in/1.88" exhaust valves, forged crank+rods, cast pistons, factory windage tray, etc.
I´m thinking of purchasing some nice hydraulic roller kits for it, to get some better power out of it but still dont have too much struggle with break-ins etc (im still fairly new to old V8 technology).
And since it will be a sort-of tribute to my (thankfully still alive) dad who owned this car in the 80´s, Im thinking of going for a Big Mutha Thumpr cam to make it sound more aggressive.
This will only be used for meets and some strip racing, pretty much a toy car, so I want that rough idle :)

But anyway, I found this kit: 20-603-9 - Thumpr™ Retro-Fit Hydraulic Roller Camshafts
Its for Chrysler 273-360 1964-2000, and requires 9.5:1 comp and headers which I have, 2800+ stall converter which I will have to buy and install, but what about the intake and gears? I dont really follow what they mean I need to have?
The engine have the stock spreadbore intake, is that enough or do I need a new one?
Also the gears, does it mean I need to get bronze gears for the distributor?

Also, if I read the components list correctly, if I purchase the Complete K-Kit I wont have to machine anything on the engine, it will just fit?
Like the Cam & Lifter Kit CL-Kit says it will require machining, but no notes on the Complete K-Kit.
Or are there better hydraulic roller cams for my engine I can use instead, thats a fit on the stock engine?
How are the specs for that cam for my engine?

Thanks! :)
 
Nidhögg said:
Hey!
This is not really due anytime soon, but I will hopefully complete my Dodge Dart 1968 with an 1971 340 engine this winter (had a new child so my time-frame got seriously kicked to the curbs :D)
Anyway, this is the high comp engine (10.5:1 if I remember correctly), with 2.02" in/1.88" exhaust valves, forged crank+rods, cast pistons, factory windage tray, etc.
I´m thinking of purchasing some nice hydraulic roller kits for it, to get some better power out of it but still dont have too much struggle with break-ins etc (im still fairly new to old V8 technology).
And since it will be a sort-of tribute to my (thankfully still alive) dad who owned this car in the 80´s, Im thinking of going for a Big Mutha Thumpr cam to make it sound more aggressive.
This will only be used for meets and some strip racing, pretty much a toy car, so I want that rough idle :)

But anyway, I found this kit: 20-603-9 - Thumpr™ Retro-Fit Hydraulic Roller Camshafts
Its for Chrysler 273-360 1964-2000, and requires 9.5:1 comp and headers which I have, 2800+ stall converter which I will have to buy and install, but what about the intake and gears? I dont really follow what they mean I need to have?
The engine have the stock spreadbore intake, is that enough or do I need a new one?
Also the gears, does it mean I need to get bronze gears for the distributor?

Also, if I read the components list correctly, if I purchase the Complete K-Kit I wont have to machine anything on the engine, it will just fit?
Like the Cam & Lifter Kit CL-Kit says it will require machining, but no notes on the Complete K-Kit.
Or are there better hydraulic roller cams for my engine I can use instead, thats a fit on the stock engine?
How are the specs for that cam for my engine?

Thanks! :)
Click to expand...
I used this cam in my first 360 Dart engine along with the matching lifters shafts and rockers. 11:1 cr with iron heads with big valves. It did sound very nasty with that cam. Stock intake with an 800 cfm TC.. lots of power up to 6000 rpm. A friend's buddy loved the sound so much I sold him the engine and am building a new stroker for my Dart.
 
cam and lifters should drop in. The hardened distributor drive gear is not needed. The machining sometimes will address the shallow lifter bores of the 340 that would otherwise uncover the oil band of a traditional roller lifter, but in this case they are only referencing the optional smaller locking valve seals and Comp valvetrain. Rollers offer more aggressive ramp rates so you ll need recommended valve springs. $$ Rollers are great for max effort motors, hydraulics still have their place too.
 
Hughes and others sell a retro roller hydraulic lifter that has the oil band located lower on the body to eliminate oil band exposure at the lifter bore top. Some people have had problems with the retro rollers in that they won't pump up due to poor/incomplete machining. I used the Hughes version in my brand new used rebuilt 360/408 LA non roller block with no machining or problems. Just get the push rod length correct and you shouldn't have a noisy valve train or problem. I would go with roller rockers too, I used the Hughes version. I didn't know what people really meant by torque monster till I put the 408 in and stepped on the loud pedal. Now I gotta find traction.
Edit: That's a pretty hefty cam, more duration than my Hughes SER3438ALN-10 but less lift. Idle vacuum will be low. Don't know about the 340 but with the comp xe268h I had issues with in gear idle and a tight converter due to low vacuum in a small bore 318. Took some time but I got it acceptable with an adjustable vacuum can on manifold vacuum and some t-port sync and idle circuit mods in my Holley 4150 650 cfm carb.
 
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If going the hydraulic roller route you will need to inspect the lifter bores on your LA and see if they are chamfered or not. Depending on what you find you will need to either bush the bores or, an easier way, use the Hughes rollers that have the lowered oil band. Check the below link for more details on that issue.
Hughes Engines
 
Whats your hp/car usage goals? As mentioned above rollers are good for all out effort, but can create problems, like you are running cast iron heads? Well you really can only get about 1.80" installed height for a spring without increasing the rocker shaft height. Which presents its own challenges. To be brutally honest I run solid flat tappet with an almost all out effort x head. I didn't move the pushrod pinch which is what is left on the table. If you are sticking with the iron head, i would go solid flat tappet. Aftermarket head is a different story. The bottom line is it can be tough to get all the benefits out of a roller using a cast iron head.
 
Don't waste your money on all that for a fun car. Don't be afraid of breaking in a cam and lifters. Ya start it and let it run at 2000/2500 rpm for 15/20 minutes- no big deal. All mopars sound great with an over sized cam and open exhaust. My-2
 
IIRC, even the Hughes hydraulic rollers sometimes don't have the band low enough for some of the 340 lifter bore chamfers. There are several threads here in the last 2 years on that topci so taking some time to look then up would be worthwhile. So the sure solution has been to go to solid rollers... but that is assuming you can find the right cam for your use in that line. There are fewer solids of any type set up for the lower RPM ranges, (if that dictated by the desired use).

BTW, I don't necessarily agree on the idea that rollers are just for all out effort. One of the key reasons is so that the lift to duration ratio can be made even higher than the most aggressive flat tappet cam ramps. It can be used give benefits all over: low, mid and high range torque.

FWIW: Knarly sound = poor mileage and, more often than not, less low end torque. They use a lot of overlap to get the sound, which costs in other areas. That may or may not be important to the OP.
 
Wht they mean by gears and intake is, "upgraded parts" which in my opinion you should look at the Edelbrock rpm intake and a set of 4.10 gears for the rear. Use headers, ported heads, 750 carb. (And 1.6 rockers IMO.)

That is a big Hyd. cam. Certain parts will need machine work. AKA, valve springs on a stock head.
 
lets see a hammer, drill, tap and die set, micrometer, inside diameter gauges.... I ll think of some more
 
I agree with what you're saying here for sure. I was wondering couldn't a custom cam be ground for the roller lifters? And at that point maybe having the cam Underground would help the lifters go down in the bourse? more for that oiling ring?
I think the reason everybody doesn't have a roller cam is because of the price right? I know our Durango does LOL

nm9stheham said:
IIRC, even the Hughes hydraulic rollers sometimes don't have the band low enough for some of the 340 lifter bore chamfers. There are several threads here in the last 2 years on that topci so taking some time to look then up would be worthwhile. So the sure solution has been to go to solid rollers... but that is assuming you can find the right cam for your use in that line. There are fewer solids of any type set up for the lower RPM ranges, (if that dictated by the desired use).

BTW, I don't necessarily agree on the idea that rollers are just for all out effort. One of the key reasons is so that the lift to duration ratio can be made even higher than the most aggressive flat tappet cam ramps. It can be used give benefits all over: low, mid and high range torque.

FWIW: Knarly sound = poor mileage and, more often than not, less low end torque. They use a lot of overlap to get the sound, which costs in other areas. That may or may not be important to the OP.
Click to expand...
 
j par said:
I agree with what you're saying here for sure. I was wondering couldn't a custom cam be ground for the roller lifters? And at that point maybe having the cam Underground would help the lifters go down in the bourse? more for that oiling ring?
I think the reason everybody doesn't have a roller cam is because of the price right? I know our Durango does LOL
Click to expand...
Yes, that cam undercut has been used as another solution; good catch. And yeah, the after market rollers are pricey. As long as the flat tappets cost 1/2 to 1/4 as much, they will stay in the mix.
 
OE Chrysler roller lifters are inexpensive
 
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