I have a 1970 350 4 bolt mains block. First off, it is possible to convert it to a roller setup right? Secondly, how much would the conversion cost? And Lastly, would it be worth it to convert to a roller setup? I think I'm going to be running vortec heads/intake with the LTR TPI setup, but it's not a definate yet.

 

Yes, it's possible.

I believe the cam and lifters will be $400 plus you'll need more stuff, not sure exactly though.

Is it worth it, is kind of up to you... it will cost, but you'll get more HP and longevity out of it. I plan to go to roller soon as I can.

With a roller you can run higher lift w/o decreasin drivability. Only bad thing about the Vortec heads is that you'll be able to run a high lift roller, which the stock springs will most likely not be able to handle.

 

yeah, im changing the springs for sure.

 

IMO, hyd. roller cams with less the ~230* @ .050" is a waste of money to convert to. The last I checked, aftermarket roller cams run about $280, and the lifters are just as expensive. So right there you're looking at +$500. Then you need new pushrods because roller lifters are taller than flat lifters, and springs because roller cams need more seat pressure than flat tappets.

Sometimes the cost far out weighs the benefits.

 

Camaro driver - your link scared the **** out of me!

 

 

Would I HAVE to get the retro-fit lifters and cam for a 1970 350 block? If I do, screw that route, they're like $400+ for just the lifters!

 

You either have to get the retrtofit lifter retaining kit AND a thrust plate / cam button, OR you can weld bosses on the existing block and machine them down to accept the factory roller setup from '87+ engines, which would include machining the tops of the lifter bores. The aftermarket setup would certainly be easier, but isn't cheap. A decent flat tappet grind starts looking better all the time, doesn't it?

 

I emailed Comp Cams, they told me I'd lose anywhere from 30 to 60 horsepower by going with the hyd. flat tappet. Man that sux, I don't know what im going to do.

 

If you have a TPI with LTRs, that will already lose you so much HP from what your motor could make with a decent induction system that a couple more lost from the cam won't matter much anyway.

If you want the max posssible HP out of a flat tappet cam and LTRs, probably the best way to get it is to pick out the roller grind that will do what you want; then get them to custom grind you one with their Xtreme lobes that most closely duplicates the event timing you want, and use 1.6 rockers. I'd suggest aiming to match their "304" grind.

And of course, the LTRs will also protect you from ever needing to be concerned with the number of bolts in the main caps, unless you're planning on adding 200 HP of nitrous. You might want to cosider trading that block to someone who needs it for a late-model 2-bolt roller block instead.

 

Funny you should mention Comp Cams. On their very own website they ran side-by-side apples-to-apples comparisons between their own line of Xtreme Energy hydraulic flat tappet cams and roller cams!

Go check it out- you'll see the difference isn't that great.

If you compare cams flat to roller based on .050 duration, the roller will kill the flat tappet. But that's the mistake most people make when comparing. To get the same .050 duration the roller cam has to have significantly more total (advertised) duration to get to the same .050 duration.

Long story short- compare them on advertised duration and on how much manifold vacuum they generate (both listed in the tests) and you'll be comparing cams that have similar "real world" behaior as far as RPM range, idle characteristics and street drivability. Once you do that you'll see they are not that much different.

Don't be afraid of flat tappet cams!! I've made boat loads of power with them for years. A full-on roller conversion is gonna run you close to $700 when all is said and done. For the money, better heads will make much more power than a roller cam conversion.

 

put your money in the heads, not the cam. you won't be able to really exploit a roller without good heads

 

hey damon where ya from in philly

 

Spend the money on heads and stuff a big flat tappet in there, you'll have more power then than going with a roller setup.

 

Which lobe would you rather have opening your valves?You can see why the roller lobes makes more power!

 

Nobody has said "A flat tappet makes more power."

The discussion is what's the HP/$$ ratio.

Sometimes the gains don't justify the added expense. I could spend $120 for a flat tappet cam w/ lifters that makes xyzHP or $290 on a roller cam (no lifters) that makes the same xyzHP.

If I spend $120, then that leaves me $170 to save for an intake manifold, or descent headers, or whatever.

So......
"Witch lobe would you rather have opening your valves?"
..... First off, I don't believe in witches ..... but I'd rather have the more cost effective one.

AJ

 

Alright I've finally made up my mind...I think. I scratched the vortec heads and decided on 190 AFR's and I will be using a hyd. flat tappet cam. With a 350 LTR TPI motor, what's a good hyd. flat tappet cam for those heads? BTW, I have Speed Density so if I go too big on the cam will I have manifold vaccuum problems?

Thanks for all the info on the cams guys, I appreciate it.

 

dude, I went thru the same debate and as others have stated, I got as much out of my Summit flat tappet cam for 79.95 with lifters .488int/.510exh and put the rest in a good pair of World product torquer's with 170cc intake runner for street and driveablility. Mine is everday driver with 2.02/1.60's and gets 20-25mpg and eats most normal "hot rods" for snacks. I have 355/4bolt main truck block and TPI in 86 T/A. Oh what fun it is to hear it Idle and then lay you in seat all the way to 5750. Of course I have all the other goodies to make the package work but the flat tappet idles lumpy with 18"vacuum at 750rpm.

 

I also opted for the hydraulic flat tappet in my 406. Spend the money saved on better heads and intake upgrades. I built a big torque, low rpm engine and it runs great. Wife's 350 roller cam engine in her 90 IROC shifts at 5500, and my 406 hydraulic cam shifts at 4500. I still run 10 mph faster over a given distance. Hers is going 60 and mine 70 where I measure. I did work on my air intake, added headers and a hi-flow cat that she doesn't have.

 

yeah tiggerman got the answer for you. The cam he mentioned has the same lift as the ZZ4 cam and you know what.......that Summitt cm is made by Crane. Not many know that. Good luck with the buildup

 

test

 

Would this be a good cam for my setup? ltr tpi 350 w/afr190's, 10:1. It was in comp cams xtreme marine section, it's very similar to the xe268, with a little more duration & wider LSA.

specs: adv. duration 270/286, duration @.050 226/236, lift w/1.5 rockers .480/.489, 112 LSA.

xe268 specs: adv. duration 268/280, duration @ .050 224/230, lift w/1.5 rockers .477/.480, 110 LSA

If anyone has any experience with any other cams in a similar setup PLEASE let me know how it worked out. good/bad, etc.