Street Cam Input Needed - Roller or HFT
 

Hey guys,

I am building a 408 for my 67 LeMans with a TH2004r and 3.55 gears. Intent is just a street cruiser and hit the highway when I want to. The engine is a .040 68 400 block, 670 heads, I just picked up the heads and will be having them gone through with new everything and get good forged pistons to get a compression to 9.5:1 max. May even go 9.25. I want to use a stock lockup stall converter

I am looking for some ideas for cam choice. I have a Lunati 702
Duration @ .050 (Int/Exh): 219/227
Gross Valve Lift (Int/Exh): .468/.489
LSA/ICL: 112/108

I was also thinking of going roller and would like recommendations. What about Howard’s 4/7 swap cams? And what’s the LS7 lifter use I’ve read a little about?
Thanks as always for your input.
Thanks

This is going to get good!Tom

hft, I would want no part of taking a trip with hyd roller. For what 10-12 HP ?
Myself, custom sft. You really do not have to adjust them all the time if you use good valve train equipment.

What’s the advantage here for a street cruiser? I have never considered SFT for any street engine.

following*


been wondering about those howards cams myself

ditto

I really doubt the 4/7 swap will add any power on a small street cam, the 4/7 swap will sound a little different. Howard’s retrofit HR cams use a stock distributer gear, which is nice. I think they are usually Sadi cores, which is not so nice, it is why they are priced cheaper and can run that stock gear. We have a pretty big .4” lobe Howards in an engine running .640” lift.

The 702 Lunati is a nice mild street cam in a 400 with 9 ish compression. With a HR cam the engine can run a bigger cam and not loose idle quality versus HFT. Would be pretty easy to gain 30 or 40 HP over a 702 by using a bigger HR cam and not loose any bottom end. Something like the 280/290 Howard’s, seems like they are 227*/237*@.050 on a 112 LSA? I can’t remember the lift, mid .550s I think.

I wouldn’t mess with the LS7 lifters. I mocked a couple up, and was not impressed. But suite yourself.

Are new cars are littering the highways broke down with those failure prone hydraulic roller cams? I've got a couple of the first Pontiac HR cam and lifter sets produced in 2002 that are still going strong and one is over 30,000 miles with no problems.

I guess the good thing about HFT cams is if you don't like the cam you chose, you can pick out a different grind in the not so distant future. :D

The voodoo cam that you listed will have excellent street manners . I run a slightly larger Bullet HR in a 406 . 226/230 , .518 lift , 112 sep . It pulls around 15in of vacuum and gets 14ish mpg with 3.90s , 4spd & Qjet . It has the 4/7 swap that I don’t really think brings anything to the table . It was just at the time I bought it (2010) , that was the only cam cores available lol I think the 4/7 swap was “ IN “ at that time . Having said all that , I don’t know if the HR was worth it either ? At the time , I made that decision based on my research and the best info that I had at that time . My 400 does run excellent and isn’t fussy about fuel or temp . I would probably go solid roller if I had to have a roller again .

Engine Masters did a show on the 4/7 swap. Advantages were nonexistent in their application.

The .640” Howard’s HR cam I have has comp SR pin oiled lifters on it. Most of my street cars have mechanical SFT or SR lifters. In my cars I prefer mechanical cams unless it is a modern engine platform.. But we have ported heads on about everything, they like more lift.

That Bullet cam is a nicer cam than an off the shell Howard’s. . The 4/7 swaps are a little more expensive when ground on billet cores.

Tuned in, this will be fun.

Im a big fan of keeping it simple, for a baby cam like you are considering its a no brainer to go hydraulic flat tappet.

Rollers are just to expensive and not worth the added complexity for what you are trying to achieve.

There are millions of hft cams out there and not going flat or self destroying. Dont buy into the Zinc scarecrow and self eating lobes. Myths of having to run exotic oils and Ebay barn find New old stock vintage oil filters because all the new stuff is crap...

YES you do have to take initial startup and cam break more seriously but after that you're all good and just run decent oils.

HFT, long slot stamped rockers, 068 iron dual plane, a decent Qjet and a cam that is NOT a new extreme fast ramped mofo (will create a rackety valvetrain otherwise) and just drive the thing everywhere.

Since cruising and OD transmission are on the menu pick a cam for that.

In one of my cars, l have a rebuilt 350 pontiac with an iron 4 bbl 068 intake, 670 heads , a small 268 cam, hooker 1 5/8 headers with a th350 and 3.36 gears and for a mild engine , it goes like stink and lights up the tires at will .

Peter.

First photo shows the hydraulic flat tappet cams I've pulled out this year. There isn't one in the bunch that wasn't showing signs from beginning failure to complete failure (not a roller cam in the bunch).

Second photo are the failures from about three years ago up to this last year. There were a lot more but a club member took a bunch to make lamps or some other hobby project.

O52 that is a member here and the GTO Forum just had a Melling cam not make it past the break-in cycle just this last month. Melling replacement for the stock 068 cam and he brought the engine up and we broke it in on my run stand. Correct oil and ZDDP additive and correct break-in procedure.

Thanks for that. What do you recommend for my build then? I’ve had good luck with HFT and the Lunati I have is around 7 years old NIB.

Too many horror stories around here.
A flat tappet cam can not ruin you block like a roller gone sideways can. And they are not making anymore OEM blocks.
Risk vs reward, nah. Little more power, much greater risk and expense.
I would run a high dollar BAM DLC solid roller lifter before I ran a hyd roller. At street pressures, no needle bearings less risk. But still not worth it.

Most new cars are OHC with valve pressures you can open with a thumb, what pushrod motors are being produced currently are using light valves and followers beehive springs and puny cams.

the Pontiac community is slooow to get on board with beehives

there has been so many iterations of retro fit hydraulic roller lifters its near impossible to keep track thats because of so much success i imagine

Just a fan of them. They were ran forever on all kinds of automotive engines.
Heck, my 07 Volvo has solid lifters.

If you go back and research all the failures, the one company that is hardly ever reported failing is Crower. Their cam and their cam saver lifters are probably the best insurance of having a flat tappet assembly last.

You might have noticed that Summit, Jegs, Edelbrock, Lunati, and many others carry the same cam profiles. One cam grinding company supplies the finished cams to these companies and they basically re-box and sell the same product under different names.

As far as hydraulic vs solid flat tappet cams, we still have the same problem with hydraulic and solid cam cores coming from the same foundry. Going to a solid cam isn't going to save you from bad metallurgy.