Tapper to roller cam conversion

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matt030305

matt030305

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Hey all, I’m looking to do a hydraulic roller cam for my 72’ 340. It has J heads with 1.88/1.60 with stock crank and bore. There’s no complete kit for a hydraulic roller cam that I could find.What would I need in order to do this conversion? Thanks!
 
So you have a particular cam picked out yet and if not, what gears, converter, rear tire, and performance goal? Low compression cast crank 340?
 
9.7:1 compression 340 with cast crank. no particular cam picked out yet but I want it to be street friendly. Looking for about 450 horsepower. 3.23 gears but converting to 3.73. Hoping to get a 2500 stall converter.
 
matt030305 said:
9.7:1 compression 340 with cast crank. no particular cam picked out yet but I want it to be street friendly. Looking for about 450 horsepower. 3.23 gears but converting to 3.73. Hoping to get a 2500 stall converter.
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You ain't getting to 450 hp with stock 1.88" J heads.
 
Heads are basically the item that determines and engines available power capabilities, to make 450 hp you need heads capable of 450 hp at the rpms you'll need to turn for your displacement to get there and work with the general cams cr intake exhaust etc... needed for that level.

A 340 gonna need to turn around 6000-6500 rpm depending how efficient for 450 hp, with heads probably around 250 cfms with a 240 @ 0.050" ish cam etc..
 
matt030305 said:
My plan is to replace the current j heads with edelbrock aluminum heads. I’m doing a top end rebuild
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That should do it with the right parts.

As for hydraulic roller, if you run a mechanical fuel pump you need a roller cam with the right snout for the pump, a set of retro fit roller lifters, push rods, and possibly the distributor/oil pump gear with the right material.
 
If you started out with a set of heads that came set up for a HR cam……….and you used all name brand stuff and stayed away from the Chinese lifters and rockers, to buy-
Cam
Lifters
Rockers
Pushrods
Oil pump drive gear

You’ll spend about $2000
 
If your motor is apart, I would highly recommend you first and foremost get the lifter bores bushed. If you're goin' roller, now is NOT the time to save money. I can almost guarantee you'll have oiling issues just dropping those pricey roller lifters into the factory lifter bores. Even if you don't, being bushed, it will live a long happy life. Trust me.

Next you need a quality set of lifters. BAM, Comp, Crane.......there's plenty of choices. None are cheap.

All you need now is a good bronze gear intermediate shaft and your cam. Easy peasy.

Last thing I'll say is consider a SOLID roller instead. I don't know why they even make hydraulic roller lifters. Checking your valves once a year is a simple 1/2 hour job. If you really take your time.
 
273 said:
That should do it with the right parts.

As for hydraulic roller, if you run a mechanical fuel pump you need a roller cam with the right snout for the pump, a set of retro fit roller lifters, push rods, and possibly the distributor/oil pump gear with the right material.
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Is there such thing as a roller cam that is compatible with the oil pump gear?
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This is going to be so expensive lol.
450hp with Edelbrock heads and a roller cam conversion, plus going with adjustable rockers if you go with solid roller lifters as suggested.
Well, if it makes you happy, go for it and make it look pretty.
matt030305 said:
My plan is to replace the current j heads with edelbrock aluminum heads. I’m doing a top end rebuild
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Car Nut said:
Too many failures with Bronze gears in street driven cars.

If you’re not racing buy a melonized steel gear.
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I'm just not buying it. I do around 2000 miles a summer, plus a few passes and have no problem. I'm pushing way more HP than 450. Bullet AND Lunati told me years ago to run from melonized gears.

You might be right but I've never even heard of a failure. Maybe people never check them. What exactly is failing?
 
This gear was installed when I built my motor in 2019. 10 or 12 dyno pulls, 5 summers of hard running. Changed it over the winter and looks like it didn't need changed.

No "knife edge" wear. Nothing but normal wear. I think it could have gone at least 3 more summers.

Also, I do not baby the thing. In my neck of the woods we run the hell out of our cars.

g1.jpg


g2.jpg
 
Ironmike said:
You might be right but I've never even heard of a failure. Maybe people never check them. What exactly is failing?
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Here is an example that was just posted a week ago. In a 440 with a solid roller.

IMG_7829.jpeg
IMG_7830.jpeg
 
I would say that these days the chances aren’t as good as 50/50 that you’d get a long service life out of a bronze drive gear.
For a bracket car, if it only lasted a season or two it’s not the end of the world.
On a street car, they can get pretty ugly in 1-2000 miles.
The key word being “can”. Not every one will wear right out, but for sure……some will.

I recommend the melonized gears for the street applications.
 
PRH said:
The key word being “can”. Not every one will wear right out, but for sure……some will.
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I sent that picture of the first cam gear I posted to a cam company, and they replied back today and said “It looks like it’s not centered on the cam”. How in the heck do you center the bronze gear on a cam?
 
I'm running a bronze gear in a stroked SBM, but it is race only. I had mine cryo'd which made it a bit harder, I have minimal wear at best and it's seen a "lot" of race time.
 
Car Nut said:
I sent that picture of the first cam gear I posted to a cam company, and they replied back today and said “It looks like it’s not centered on the cam”. How in the heck do you center the bronze gear on a cam?
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Making sure the cam sprocket is setting the gear the proper distance from the face of the block, & using an effective, positive method of preventing the cam from walking forward, if it moves around it ain't gonna last long.
 
Killer6 said:
Making sure the cam sprocket is setting the gear the proper distance from the face of the block, & using an effective, positive method of preventing the cam from walking forward, if it moves around it ain't gonna last long.
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Then using a reinforced timing cover should solve that with a cam button?
 
Yes, and I prefer a solid not spring loaded setup, with or w/o a bearing. In this case, the SBM has a retaining plate to locate the cam already, it just has to be up to the task/materials involved. The distance of the gear position should still be checked, just 'cause......
 
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Car Nut said:
I sent that picture of the first cam gear I posted to a cam company, and they replied back today and said “It looks like it’s not centered on the cam”.
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And yet, I’d be willing to bet the factory gear and cam looked fine after 100k.
 
There was a thread about this over on Moparts a year or two ago.
Basically, the OP had a BB that was chewing up bronze gears in short order.
He ended up going to the melonized gear, and he pulled it out a few times for inspection.
It looked perfect each time.

As always……ymmv

Here ya go…….

Bronze gear wear
 
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