Flat vs Roller, Blown 454
 

Good morning OSO,

I'm working on readying the long block of my 454 Mag for a 250 B&M setup that I bought a couple of weeks ago from another OSO member. Right now I'm trying to get the valvetrain piece sorted out.

I've read conflicting threads about whether or not a hydraukic roller is necessary in this setup. I believe Bob Madura added his comments on why it isn't necessary. Aside from the relaibility factor, am I really leaving s lot on the table by NOT going roller? Seems to me that I can do quite well with a flat tappet and maintain a stable valvetrain (vs some of the headaches of setting up the roller).

Here's my setup:

454 stock Magnum short block
ProTopline/RHS 300cc head (rectangular port)
B&M 250 with twin Nickerson 850s
496 HO manifolds and risers (risers will be extended)

Anyone got a flat tappet cam recommendation? My goal is 600 HP. From what I've been reading it shouldn't be hard to get to with this setup.

Comments and feedback are welcome!

well you should talk to Bob M. as far as the selection, go with roller now, major issue with the flat tappets are the cores that everybody uses to grind from...mostly junk material, so along with the oils you have a bad situation on getting them to live...

Agree w/EZ talk to Bob Madara or Eddie Young and they will give you the lowdown.

I have talked to Bob about a cam set up in my 525sc and he quoted me for a roller set up

The valvespring psi you'll run on your SC'd 600HP'd HFT cam will be enough that you'll need to upgrade to better cam cores and better lifters.

These are still no guarantee you won't have wear problems, even with right oil and break in procedures.

You'll also be not too far away $$$ from what a HR set up will cost.

in this day&age it is foolish to use a flat tappet camshaft.every production engine comes with roller,s today for a reason.yes the initial cost is higher but you will sleep better knowing that it will never go flat.i am pretty good at selecting a camshaft from a book but now i call bob madera for almost every build i do.his knoledge is amazing and his prices are the same or less than the big cam company,s.

I'll send Bob a note this afternoon and get his take on the whole deal. He's definitely the expert here. Anyway, I thought it was a pretty interesting topic.

What do you guys think regarding my HP goal? Doable more perhaps? Or am I asking too much?

Thanks!
TZ

I have a 525sc which has the 177 weiand, and Bob said with going roller, and his custom ground cam he sees 100hp over stock. So I am thinking 600-625hp with the roller cam upgrade in my application. If you aren't familiar the 525sc is a 454 with 7.5:1 compression, 088 heads, 177 weiand blower with 1050 dominator.

Yes, I'm familiar with the 525SC. Originally, my thoughts were to clone the platform, and then the 250 deal came up (couldn't pass it up), so now here I am. I know thr added compression of the 454 mag helps crutch-up the 177 in a good way. Not sure how much more the 250 is worth here, but I'm sure it'll be more efficient.

Is 600 HP being conservative?

I would say 600hp is conservative for your set up. I believe a stock 454 mag is 8.7:1, and sounds like you have the dual carb set up for the 250? I am not familiar with your heads. The 088's are a limiting factor on my set up, they will basically be maxed out at 625hp, but so will the 177 blower. I would say with a 250 dual carb set up on mine at 5-6psi of boos, bumped compression, Bobs roller cam conversion, and a good aluminum head probably around 675-700hp. In your scenario the only factor that is different is how good your heads are, and if you do the full roller set up from Bob.

250 is a no brainer over the 177. I contemplated doing that, but plan to sell the boat in the next few years and what the power platform to stay relatively stock. If I went to the 250 I would need to do heads as well. So my plans are the full roller set up from Bob first, then when or if rebuild time hits, a flat top piston to increase compression. If I keep it long enough then I may swap out the heads and the 177 for a 250 or 420. You made a good move with the 250

600 with a 454 250 is about right. you could get more but it starts getting expensive-eating drves etc....

The blower was from me. Came off a flat tappet cam'd,iron headed 502. That made my 25 Daytona run 95mph gps supposed 653 HP dyno

Mike would you recommend switching to a roller set up on a stock 502 for reliability purposes? Could it be considered a first of several stages of power increases? or would it make more sense to do it all at once?

I helped oso member "WAYNE272" a while back picking out some parts for a similar build. He had a pair of stock 365HP mags. He bought some 177 blowers, single carb, crane flat tappet cam, crower cam saver lifters, basic rebuild on the hard parts. Engines made somewhere around 580HP at 5400RPM, with only about 4.5lbs of boost. Torque was over 600 ft lbs.

That same combo with a 250 blower, twin carbs, 5-6lbs of boost, should easily make 600 or 625hp.

Without a doubt roller is the way to go. Flat tappets can work though, they did for stock 575sci's, 600sc's, 800sc's, 525sc's, and plenty of them out there still running around.

I would have to highly suggest if going with a flat tappet, the crower grooved lifters, a quality oil with plenty of zinc, a good cam core, and proper break in are a must.

Keeping the cam lobes coated in oil is a must. The grooved lifters help with that. Back when I ran flat tappets (non grooved lifters), whenever in long no wake zones, I made it a habit of putting them in nuetral and reving them up once and a while to splash some extra oil on the cam.

That's flying!!

I had a nice conversation with Bob Madura a couple of hours ago. Always a pleasure talking to him! He knows his stuff!

In our conversation we pretty much came to the understanding that moving to the roller set up is good investment for the longer term even if the current short block were to go south over the next couple of seasons. The first order of business: inventory of all the parts.

My heads are comparable to the 088 head, maybe a little better. Some flow numbers would be good, but he seems to think that with a once over to refresh (and a check of the bottom end), we can get 650 HP out of the combination pretty easily, and that 700 HP is pretty attainable using one of his cams. It won't come cheap though (does it ever?). After all is said and done the valvetrain will probably run me another $1300-1400. Time to start saving those pennies!

We discussed flat tappets a little. The available cores and lifters are the issues now. They can work, but they're almost impossible to get the longevity out of them.

i think it would be wise to do all the mods at the same time.it would save you money in the long run.