Hello,

I have a new 470 stroker built out of a 400 block on an engine stand. It currently has a Comp solid flat tappet cam and has been run for about 1 hour total. Before it goes in the car, I have been contemplating moving to a roller type cam to avoid failure of the flat tappet cam. As far as I know, the engine is 100% healthy, however I am very concerned that there will be problems as a friend had the exact same combination and his went bad. My question is how difficult/what needs to be changed to make the conversion? Here is a list of my parts in the engine:

400 Block stroked to 470
Trick Flow 270 heads
Harland Sharp 1.6 rockers
Smith brothers pushrods
Comp solid flat tappet cam

If I need to provide any more information please let me know. Thank you.

straight forward swap, you will most likely need shorter pushrods as the hydraulic roller lifters are longer than the flat tappet ones. Other than that, simply change out the cam.

You’ll also need a billet camshaft compatible oil pump drive gear, and camshaft thrust control.

Depending on which spring package your heads have you may need an upgrade there as well.
If you go solid roller you can pretty much just assume you’ll need the springs upgraded.

Plus degreeing it in and checking valve to piston

What kind of power are you looking for, what intake, carb and headers do you have? Is this race or street strip, or just street?

If you are drag only, a roller is a much better choice. What is the compression ratio of your engine?

I put a Comp Cams solid roller in my old iron headed gas low compression street Duster motor, it was ground on a 108 LSA and I installed it at 106 ILC. It had .420 intake lobe lift with .409 ex lobe lift, 260@ .050 intake lobes with 266 @ .050 exhaust lobes
That motor ran excellent, sounded really nasty below 2000 RPM and pull like a young horse hit in the butt with thin whip
I did a lot of parts changing on that motor, top end, heads, intake carbs and rocker arms same short block and cam and lifter
It responded well to all the changes, it ran 10.70s @ 124+ MPH to start with and ended up running a best of 9.993 at 134.6+ MPH corked up on Oregon 92 octane pump swill weighing 3450 lbs. with me in it
Lots of fun

I would be calling Dwayne Porter, sending him your heads for porting and using which ever cam he recommends. Then get a custom, high-quality torque converter matched to the new head & cam combo. Disregard this last advice if you run a manual trans.

Rollers are less problematic, but...If you've already got a cam in there and it's properly broken in...if you don't have issues now....why would you necessarily have a problem in the future?

Most of the FT issues that I'm aware of were due to improperly machined Lifter that have no taper at the bottom, so they didn't' spin in the bores.When they spin the amount of actual metal that makes continuous contact on a flat tappet in motion is surprisingly little.

Also some cams post covid had some horrendous QC issues....like no holes bored in the Cam journals for oil passage...WT...?

But I've got a little Circle track flat tappet in my 426" Windsor Ford stroker 351 that's been in there almost 30 years. Still runs great....and I expect it will continue to.

If you are ok with the current performance, you could buy a stethiscope, listen to the motor warm, then check often for increased noise. As long as you run the best hotrod( hi zinc) oil, and keep an ear to it, it may last indefinately. Should you hear a "tic" develop, time to pull a valve cover and start digging for the cause, before it saturates the motor with iron dirt.

Sorry that this reply has taken me so long to post. To answer a few questions, the engine has break in time only ( about 1 hour total).

The reason I am worried is that a friend of mine had his engine done ( a 500" wedge) and is experiencing problems in the oil pump drive area, specifically where the cam gear engages the oil pump drive and distributor shaft. I am not sure if he has torn his engine apart to see if the lifters or cam lobes are prematurely wearing yet. His is in his car already with hundreds of miles driven. Mine has the same cam, built at the same shop and I have not put it in my car yet. Currently I can't start it but I could take out the lifters and check them along with the cam lobes. My thought was if this situation is going to happen eventually to my 470", then now is the time to put a roller cam in it before it goes into the car. Here are the specs on my engine:

470" short block with Ross pistons, Eagle rods and Molnar crank. ( Molnar rods were not available when it was built)

10.5:1 Compression

Trick Flow 270 heads with Harland sharp rockers( 1.5 ratio)

Trick flow intake port matched to the 270 heads.

Holley 950 HP carb

Comp 23-233-4 Cam, solid flat tappet, 252/260 @ .050, .540/.588 lift, 110 LSA ( XS290S grind)

Do you have lifters with the oiling holes on the face? If your lifters have oiling holes and if it broke in fine without any changes to the lash then you should be good to go. Check the last every 100 miles for the first 1000 miles and if the lash never changes then you might be fine.

You can change over to a roller but it will cost you $2000 or so these days in parts. Cam, lifters, bronze pump gear or melonized gear if you can find it, shorter pushrods, valve springs and maybe retainers or cups. You'll also need intake gaskets, timing cover gaskets and some sort of cam button plus a few hours of shop time. This assumes that you can do the work yourself and have a degree wheel, dial indicator, basic hand tools, etc.

Are you thinking of going with a hyd roller for mostly street use, or a solid roller for mostly drag race duty?

The investment of $2000 now seems steep, but if the flat tappet cam goes bad you'll have to pull the engine and do a full rebuild. Typically when a cam goes flat the engine needs a full rebuild since a bunch of cast iron powder gets circulated thru the oiling system. If you catch it immediately by keeping a close eye on the valve lash you might not need a full rebuild, but many people drive for weeks or months with a flat lobe and end up trashing the entire engine. We just had a BB Chevy engine come in the shop and most of the lobes were flat. It was an old Crane hyd flat tappet cam and it was worn down to a nub. Two of the pushrods were broken in the process. Needless to say, it needs a full rebuild.

We don't put flat tappet cams in anything anymore unless the owner swears on a bible that he is okay with the flat tappet cam going bad and ruining the entire engine.

A couple of considerations pertaining to the costs…….if that matters.

If the heads have the 1.55” spring package, nothing would need to change on the heads for a HR swap.
You can plan on new springs for a SR.

If something like Smith Brothers pushrods were used, then can probably be sent back and shortened.
Tubing diameter, thickness, hardness for a SFT should be adequate for a HR, but might not make the grade for a SR.

Lifter wear and tear is generally higher with SR cams because of the faster ramps and higher spring loads.
That also carry’s over to the rocker arms.

None of that is really much of an issue on a drag race car that will rarely see any street miles.
But should be considered if the primary use will be street duty.