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stock headed 454 help

3K views 18 replies 11 participants last post by  pockets 
#1 · (Edited)
First of all, good morning to all of you wonderful people here. I have been told this is the place to go for solid engine advise.

Little back log here:

Application : Sunday cruiser with some highway use (they live in a small town and highway is the way to the city) for mom and dad. Good drive-ability with some pep when the old man wants it.
Car : 1969 Camaro (I know its not a chevelle, sorry)
Motor : Stock (as far as I know until we pull it out) 3999289 block with 336781 heads
Trans : TH400 (figuring likely a 2200 stall depending on what you guys say for cam)
Rear : 12 bolt with 3.08 gear (really dont want to go any higher for sake of highway driving)
Intake : Edelbrock Performer RPM
Carb : Holly Street Avenger (assuming 670cc, but not 100% sure until I get it pulled off)
Exhaust : small long tubes (dont know the tube size, have not measured yet)

OK, so I think that is a decent enough back log, if not, PLEASE let me know what else you need.

So, over the past days I have been scouring this forum for a cam choice. I want something thats going to have enough low end to overcome the crappy (IMHO) 3.08 gear, but also make some power for when dad wants to let it eat. (we dont need massive amounts here)

I have more or less decided on (unless you guys say otherwise) the Lunati 60203 cam. I was going to get their complete kit which included lifters, cam, timing chain set, springs, retainers, locks.

Assuming the engine has flat tops and is low compression (judging by the casting number of the head and block Im going to assume that it is) will this cam be OK to stab in there with that low of compression? Or is it going to eat up all power that would be left on the bottom end?

If it will work alright, do I need anything special for the heads to get rid of the rotator's on the spring cups? Im assuming the Lunati Kit is installed without the spring rotators? Or do their spring choice already compensate for that?

I know Ill need some long slot rockers, and just planned to get stock stamped pieces.

Thanks in advance for any help!!! Its greatly appreciated!!

Rodney Pierce
Marion, IA
 
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#4 ·
Thank you for the details for us to make a decision here. So many times on here we get a 2 sentence description and they want to know 10 different items from their limited description. You laid it out nicely here. The cam you have sounds good for what you are doing. It may be a few more bucks but you might want to consider a hydraulic roller with similar specs. Just and idea you would pick up some HP but it would cost some more money as you would need roller rockers and roller lifters and the cam core is more expensive - but at least you get something for you money. Also better check your piston to valve clearance before you start on anything - keeping the duration short like you have will help. One thing nice about the roller is no pesky cam break in.
 
#5 ·
I like the hydraulic roller idea like Lew stated.............abit more power and no break-in worries, also no fears with a lobe going flat which I look at as kind of an insurance policy.

One other thing, IMO I'd go with a well tuned quadra-jet carb and Performer RPM Q-jet manifold. Not a better carb out there for a stock-to-mild BBC.
 
#6 ·
If your having the engine out, and if your taking the heads off to get rebuilt or valve job, might consider doing just a little clean up port work on those 781 heads. That would sure wake up this motor. You wouldn't even need to put in larger valves if you didn't want to spend the money. You could just touch up the bowls and smooth the casting seams in the runners and you'd be happy with the difference. Do the port work before you have a shop do a valve job, just incase you nick a seat or something like that. It wouldn't have any negative impact on highway driving or ease of driveability.

If your not planning to do anything with the heads, then the above advice is what I would follow. Hyd roller is a good idea, but if you didn't want to spend the money, don't be afraid of the flat tappets. They been ran forever, just break it in right with the right oil and you should be fine. Rollers are easier for sure, but flat tappets work as well when broke in properly.

Your on the right track. Read all you can and enjoy the father son project, sounds pretty neat to me.
 
#7 ·
Thanks guys!!

I'm afraid hydraulic roller is out more than likely. As much as I would love to put a nice setup like that in, it's not really in the budget. And, it's a pretty mild cam really.

I'll break the flat tappet in correctly. With good oil and additive (zinc).

I also planned to have the heads decked .030 to raise the compression a little (if even just half a point)

PTV is a good idea! I'll check that before disassembly and report that back here on the stock can, and then we can go from there, but from what I gather, this is a pretty popular can and I have not found any fitment issues or tight PTV clearance problems listed. (Not that it's not a very valid point to double check!!)

So everyone thinks we will be OK on the bottom, even with the lack of compression? I can also touch up the ports more than likely (remove casting flash) before we send them off to the machine shop to get checked.
 
#10 ·
You're looking at 8:1 compression for that set-up. The pistons will be flattop with valve relief. Later engines had the dished slugs and 7.8:1 CR. Anyway, the pistons sit .023" down in the hole.

Plan A: You can locate shim head gaskets to bump the compression a bit or shave the heads, or BOTH, get the CR up a bit.

Plan B: Go get some 063 or 290 casting closed chamber oval port heads, bump your CR up to 9:1

Plan C: Simple cam and spring change.
v1: custom cam designed to make the engine think that it has more compression
v2: install any new cam more advanced, makes the engine think that it has more compression
v3: most perf cams are ground a bit advanced anyway so stick something in there, 60203 is fine.....

NO MATTER WHAT YOU DO, a well tuned 454, most any kind of moderate perf cam, is gonna make that 3400 lb 69 Camaro move. FOUR FIFTY FOURS rock, compression and gearing are not so critical like on small block stuff.


FWIW, SeatGuy Ben started with a 454 that i sold him the parts to. Low CR deal with a small 270* cam. A weak later I sourced him some small chamber heads, took back the 781s etc. Then he went and got a 60203 cam. Should be a strong runner
 
#11 ·
2009, I did the same thing Ben is doing in the post above...low compression shortblock, early closed chamber heads, moderate PERF cam. with a whopping 4000# (70 El Camino, 230# of handsome driver, fuel) moderate 3.42 gears through a 2.5" exhaust system. True street. The first passes were 13.4s at just over 100mph. Later that summer, 6-7 outings later, 12.78 at 104.99 or there about. Throw this in a little flyweight 1969 Camaro....figure 500# lighter, 12.4 sec capable
 
#18 ·
Even though you might be dealing with low compression with a cam spec you have mentioned, run steel shim gaskets for about a .5 bump in compression and rule of thumb that seems to hold, every .006" shaved off the head is about 1cc smaller chamber.

I wouldn't get crazy with shaving the heads, just causes headaches with intake matting if the machinist doesnt compensate for that on the intake side, the steel shim is already bringing the head closer any additional removal on the head start to mess with geometry. Maybe just a nice clean up on the head surface should be fine.

Also take the time to measure push rod length and use proper length push rods, otherwise you will eat up the valve guides in short order, it's worth taking the time and checking.

Timing will be important with a some what low compression engine and slightly larger cam, you will want to dial in much more timing in a combo like this, ( really it's important to have the timing right in any combo but just trying to stress you get a lot in return taking the time).

If you just slap a dist in and set it at say 10-12 degrees btdc, your leaving a lot on the table for low end grunt, spend the time getting the timing dialed in (as much as the engine will take and quickly as possible to total timing)and you will gain a bunch of low end grunt and throttle response, plus it will keep the engine cooler while cruising around and just make the engine smoother and flat out more responsive even with 3.08 gears.

Hope this helps
 
#19 ·
I put together a top end for a mid 80's truck shortblock I pulled out of my Nova and sold to a friend. 340204 Z17 pistons approx 4.6cc. Hypereutectic flat top with a dish and one valve relief.
I went with a pair of AFR 265's, performer rpm air gap, GM performance valley pan, quick fuel HR780VS, custom straub hyd roller, straub tech rockers, 1 3/4" headers with full 3" dual exhaust and ultra flow mufflers. With the as delivered afr 265 109cc chambers it has approx 8.25:1 compression. It runs on 87 octane fuel, and I set the timing curve with 18 initial, 18 centrifugal, all in by 2500 rpm, and 12 degrees vacuum advance.
It's in a 80 chev K20 3/4 ton 4x4 with 39.5" tires. It smokes those tires from a dead stop on the highway without brake torquing. And in the dirt throws rooster tails from both tires at 50 mph.
I would look for a set of closed chamber small chamber volume heads, and if you have larger valves put in they must be cut to unshroud the valves. This will up your compression. Then a custom spec'd cam will make the combination.
 
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