Camshaft Recommendation

[Sodbuster]

We are getting ready to start work on a new engine combination our Bracket Car. GM, G-Body, 3000 lbs, stock type suspension, Power-glide with a 5200 rpm stall converter, 9" slicks, 4:56 gears. With the old 421 SBC the best run was 10.42 @ 127 with 1.44, 60' time.

The new engine will be a 4.125 bore X 3.625 stroke SBC. Bowtie block. Profiler 176X CNC 23 degree heads with 2.125 intake valves that are advertised to flow 325/213 @ .600 lift. Scorpion 1.6 rockers with a Jomar stud girdles. Team G intake with an APD 950 cfm carb. We haven't ordered pistons yet, but will be looking for a domed piston with around 14.1 compression.

We are not wanting to build a high RPM monster, hoping to stay under 7800. What would be your recommendation for a S/R Cam and lifters.

Thank you-all in advance. Any advise will be greatly appreciated !!!

[Newold1]

I am curious for your reason to go from 421 inches to 388 inches? Seems as though those 33 inches are gonna give up some good power. I know there are a lot of well done 421's out there easily spinning 7500-8000 rpms without a lot of issues and your heads by cfm withe right camshaft should get you there.
I am not a big fan of that intake manifold and even the better picks there can benefit from some good rework to stay up and use those heads to their full potential. If you are trying to make more power and go faster in my humble opinion GO BIG SON ! Sorry, had to say that!

[Sodbuster]

I really wanted to build another 421 or 434, but found a smoking deal on a new 4.125 Bow-tie block with a new Lunati 3.625 stroke crank, and 6" Lunati Pro-Mod rods. Its not really want I would like to build, but it's what I can afford to build. I am concerned about losing the cubic inches, but in Bracket racing it shouldn't matter, but my ego is having a little trouble with that. Thanks for your reply !!

[statsystems]

At that stroke you can easily turn 8200 but I wouldn't do it with stud mounted rockers.

Shaft rockers are damn cheap any more.

[Sodbuster]

I was hoping to re-use as much of my existing part as possible. A new engine was really not in the plans this year but the old 421 is about to give out.

[Newold1]

If this bow-tie block has the simeased cylinder walls you can bore it to 4.155" and that will get you too 394 inches.

If you use the 7/16" size larger threaded rocker studs and. The HD roller rockers and a good rocker girdle, lightweight valves, spring retainers and a good camshaft design you can easily see 8000 rpm operation.

[MadBill]

At that stroke you can easily turn 8200 but I wouldn't do it with stud mounted rockers.

Shaft rockers are damn cheap any more.

Ummm... $1,400 from Summit for "how long will they last?" aluminum or $1,800 + for real steel Jesels isn't 'damn cheap' in my world, even without the 35% exchange rate to the top of the continent..

[Sodbuster]

Yes this block does have siamesed cylinders, and the 4.155 bore has been considered. The heads have good 7/16 rocker arm studs, the Scorpion roller rockers are decent, as well as the Jomar stud girdles. The valves, springs, and retainers are not the very best, but are not the cheap stuff either. Thanks !!!

[pdq67]

I hope Big Joe 1 chimes in here...

Reading right along on the side.

pdq67

[KnightEngines]

Ditch the team G for a holley 300-25 or a super vic.

272/280 on 110 centres, .440/.420" lobes or thereabouts.
Actual cam guys will probably have a better recommendation, but that's my WAG.

[statsystems]

At that stroke you can easily turn 8200 but I wouldn't do it with stud mounted rockers.

Shaft rockers are damn cheap any more.

Ummm... $1,400 from Summit for "how long will they last?" aluminum or $1,800 + for real steel Jesels isn't 'damn cheap' in my world, even without the 35% exchange rate to the top of the continent..

I didn't know the OP was WAAAAAAAY up yonder. And I don't really like spending some ones money if it can be avoided (lord help him if he has a budget...I'm like a drunken whore when the ship is pulling in port. That's right, I'm spending it ALL!

So if the OP wants to use what he has I'm all for it. Like someone else said...7/16 studs and a very good girdle and you can still turn it 8000 and not worry too much about it. The OP will need to be fairly cautious and inspect the valve train often. Keeping an eye on things just so nothing sneaks up and bites him in the ass.

If the OP is willing to use quality parts he can spin that thing 8200-8400 all day long and twice on Sunday.

I say go for it.

[greg]

u can call joe or cam king even though they differ, an even the cam manufactures ,then decide,i jus got done wit a dart block shp, 400,afr 220, ole ones preeliminator they call them was goin 127,,10.30 40,s depending on heat of day, off ft brake,carsruns better,135 60ft,10.5 firestones ,slapperbars,13.5 comp ported myselfi went down in duration15 degrees same lift,, istalled on 101 was 105 crower roller,i had alot of piston to valve to much i was told,i might need more cam i have plenty here old roller cams...crower 00431 roller in it now,got off ebay new half price an ss new rollers,which will work fine,all old stuff ,but was new,,,stock dana 60 35 spline posi the good i outta 69hemi cuda,wish i cud put a pic on here, mine to big it says,green an white 55chey 2 dr hdt,i run at bfield ,good luck an HappyNewYear to all

[Sodbuster]

Thank you-all for your suggestions !! A different intake manifold could possibly be in the budget. I will start looking for a used 300-25 or a Super Victor. Thanks again !

[CamKing]

Cam# SBCR R80444-82436-110
266/274 @.050"
.444"/.436" Lobe Lift
110 LSA

If you need a .842" lifter with offset pushrod seats on the intakes, that's our part# XLR-8R02
For on-center pushrod seats, that's part# XLR-8R01

[mark_follweiler]

Thank you-all for your suggestions !! A different intake manifold could possibly be in the budget. I will start looking for a used 300-25 or a Super Victor. Thanks again !

yes, an older USED 300-25 if you can find one. they fit better.