LS6 cam or Modern equiv in SS454 Monte
 

ok, i know this is a yenko page - but i also know alot of you guys run in FAST and Pure Stock....

so - i own a 70 SS454 Monte - It has the original LS5 - but previous owner put 9:1 flat tops in, and left the rest of the motor stock including the LS5 hyd cam.

The car has its TH400, and 3.31 posi - i've been tweaking it with timing and carb tuning this year and finally have it running quite good but as usual, its not enough [img]<<GRAEMLIN_URL>>/laugh.gif[/img]

so.... i was thinking, i have an original OE LS6 camshaft, and a set of closed chamber oval port heads that have been mildly ported and LS6 valves/springs installed - they had some bowl work done on the exhaust side. They would bring compression up to about 10.25:1 - (10.5 if i use a shim gasket like they did back in the 60s)

Question is - for a regularly cruised vehicle - should i go with this LS6 cam, have Cliff Ruggles mod the Qjet for the cam and run with it - or sell the OE cam, and go with something modern that will work with a 9:1 454? I'm a sucker for original equipment HP stuff... but i don't want to put too many mismatched parts on this car.

i intend to keep the stock manifolds and functional AC [img]<<GRAEMLIN_URL>>/laugh.gif[/img] i know more than a few guys who drive ACequipped L72 cars around Detroit without issue - but they are Camaro's not the big Monte!

Any help would be great.

Cheers

Aaron

Re: LS6 cam or Modern equiv in SS454 Monte
 

Since no one has stepped up, I would say that wouldn't be a great match, as the LS6 cam was engineered with 11:1 comp not 9. I suggest contacting a Eric at Vintage Musclecar parts- a sponsor here and give them the specifics for their recommendation. IMO LS6 cam in 9:1 motor would be a dog or worse. I know this firsthand as I have been there and done that, Eric knows his stuff

Re: LS6 cam or Modern equiv in SS454 Monte
 

Talking with Eric is a good idea...he knows his way around the BB Chevy motors.

wilma

Re: LS6 cam or Modern equiv in SS454 Monte
 

I would stay away from any flat tappet camshaft...asking for problems.

X2 for Eric!

Re: LS6 cam or Modern equiv in SS454 Monte
 

Do yourself a huge favour and get with a cam guy like Chris Struab and get something for your set-up. Best money and results going that route.

Re: LS6 cam or Modern equiv in SS454 Monte
 

Aaron;

What heads are on your engine now?--they should be closed chamber oval ports (290 castings) if they're `70 LS5 heads.

Assuming a standard bore and flat top &quot;rebuilder&quot; type pistons (which usually wind up ~.020&quot; or so down in the hole) with a ~3 c.c. intake valve relief, a 106 c.c. chamber and a .018&quot; steel shim head gasket, compression would be roughly 8.8-1. I definitely would <span style="text-decoration: underline">not</span> run the LS6 cam with that combination, esp. with a stock converter, a 3.31 gear and A/C.

The factory LS5 cam isn't bad, but there is room for improvement. A mild hydraulic roller would be a nice addition, but given your constraints, I'd advise erring on the conservative side. If you're willing to take the chance on a hydraulic flat tappet, there are ample choices there as well.

In all honesty, I think you'd find more performance improvements in a good torque converter and some more rear end gearing than you would in a cam swap. A quality free-flowing exhaust system is also paramount.

Re: LS6 cam or Modern equiv in SS454 Monte
 

yes they are 290s - i've not been into the motor yet - but the previous owner swears that the measured compression with standard felpro gaskets - was 9:1 but assuming they used off the shelf parts - perhaps comp is a tad below as you suggest..

the LS6 cam is officially off the table for me - I have (what I thought was a NOS LS6 - turns out its a NOS 181 and while i'd love to build a 12.5:1 ZL1 - it ain't in the cards now - and certainly not for this monte)

i have a set of closed chamber heads from 66-67 - I think they are 206 heads from a 396 - and they have 97CC
i figured, cut em a few thou, run the shim gasket - that'd get me dang close to a true 10:1

that all being the case, they don't have the sending unit ports in them, and the intake doesn't allow for one either.

where else could I put a temp sender? that is if I want to run the factory style intake, or even the 390hp aluminum qjet intake (def want to keep it factory appearing)


i'm not afraid of a flat tappet cam - especially with GM EOS on the shelf - but a hyd roller isn't out of the question.... but I don't want to get into full roller rockers unless they fit under the low profile valve covers... i do haev a complete set of the LS6 long slot rockers - they were on the engine that teh 181 cam came out of so i'm sure they can handle the 600 lift... just not sure how good of an idea it is to use stamped rockers with a roller camshaft....
cheers

Aaron

Re: LS6 cam or Modern equiv in SS454 Monte
 

(*edited* info re: intake)

If an aftermarket intake is an option, there's the Edelbrock Performer, Performer RPM and the GMPP oval port 12363420 intake. All have temp sender provisions and will accept a Quadrajet, and if the OEM look is a must, a little orange paint goes a long way.

Stamped steel rockers will be fine with a mild hydraulic roller.

Re: LS6 cam or Modern equiv in SS454 Monte
 

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: VintageMusclecar</div><div class="ubbcode-body">(*edited* info re: intake)

If an aftermarket intake is an option, there's the Edelbrock Performer, Performer RPM and the GMPP oval port 12363420 intake. All have temp sender provisions and will accept a Quadrajet, and if the OEM look is a must, a little orange paint goes a long way.

Stamped steel rockers will be fine with a mild hydraulic roller. </div></div>


well, i'm more concerned about having factory parts - and there were several 427-390 hp intakes that I could use.

but is that 3/4- 1 point of compression worth the headache by switching heads and all if i'm gonna go with a modern hyd roller cam?

Re: LS6 cam or Modern equiv in SS454 Monte
 

Eric -- so what about roller lifters ... some are junk and will not last on the street ... TAZ [img]<<GRAEMLIN_URL>>/dunno.gif[/img]

Re: LS6 cam or Modern equiv in SS454 Monte
 

Taz;

A good set of GM, Crane or Morel hydraulic lifters should live just about forever on a mild cam. If you're talking about aggressive HR or solid roller cams, then lifter choice depends on the lobe profile. I've learned the hard way about running an .842&quot; lifter on an aggressive lobe. Milder stuff is fine but you still need to inspect the lifters regularly. On solid rollers--if you start seeing lash variances pop up, problems are right around the corner.

Back to Aarons goals--I would spec a mild custom hydraulic roller for his application.

Re: LS6 cam or Modern equiv in SS454 Monte
 

I installed a GM 502 HO roller #24502611 in my Dad's '71 Chevelle. It's a 402 but it really woke it up. I'm sure it make an improvement over a factory LS5 cam. 510-540 int, 211-230 exh. 112 intake centerline. Use can use a GM front retainer plate that eliminates the need for a cam button. You must change to the recommended distributor gear though. We used Morel hydro roller lifters and GM push rods.

Re: LS6 cam or Modern equiv in SS454 Monte
 

the roller lifter is and always has been my concern - i'm fine checking lash once or twice a year - but i don't want to have to deal with a roller lifter going south - which is why i've avoided them, and run flat solids with good oil and have never had an issue... but i've not run any of the super crazy profiles either. I'm about to install one of Chris Straub's solid flats in my 421 SBC

i drive my cars - want them to perform well when I step on it. - the Factory Hi-Po stuff has always been enough for my enjoyment - which is why i originally considered the LS6 cam over the the LS5 - but i'm not in a position to rebuild the motor and go for the 11:1 it wants.

Re: LS6 cam or Modern equiv in SS454 Monte
 

This is a great thread...I enjoy these tech discussions because I always learn something new. I have used the 502 Hyd. Roller cam in a mild 454 and it works well. Eric is right on the money that a better convertor and a little more gear will really help the performance. ATI offers a great lineup of well made convertors...their tech guys are good. A move to 3.55's or 3.73's will make a huge difference in the seat of the pants and down the road.

You should make the cam choice and any head changes prior to getting the convertor. Those 290 heads are good castings...and can be even better with a little massaging. As for the intake, you have a cast iron low profile now..if a factory unit is what you want, the only aluminum choice is the 427/390hp unit...but it is a low profile model. A 163 rect port or a Weiand Stealth painted orange are two more choices to consider.

Give Eric a call before you pull the trigger.

wilma

Re: LS6 cam or Modern equiv in SS454 Monte
 

Aaron, any updates on this?

I personally would NEVER run an OEM cam as they are such a compromise over just about anything out there. With the technology that has come out in the 30 yrs since that LS5 was made is night and day. With a few &quot;minor&quot; tweaks, that LS5 even with 9-1 comp, can make the power of an LS6, proven many many times by a number of guys out there.

I will admit, the stock manifolds I have no idea what that will effect. IF it were me, I would swap out the heads for the mildly ported oval port closed chamber heads, get the matching manifold and have it ported, and get a cam from a cam guy. In Detoit, talk to Chris Uratcko or even Mark Jones on here. The cam,heads,intake to manifolds is the package that needs to all work together to be there best.

FYI, I have a mild 427 with the ported closed chamber oval heads, flat tappit, but 12-1 and a strip dom intake with heads. Been mid 10.'s back in the 90's with it and it's set-up for nitrous. Was very very street friendly.

Or check out Mark Jones's build here for an idea:

https://www.yenko.net/ubbthreads/ubbt...opics/646361/1

YES Mark did put on some things you don't want (intake, headers, el. water pump drive) but you can get the idea

Re: LS6 cam or Modern equiv in SS454 Monte
 

i havn't done much of anything yet - i learned that the cam I thought was the L72/Ls6 cam is actually an old ZL1 cam - so i'm gonna try to sell that to pay for a new cam... no luck yet!@

Cheers
Aaron