still haven't bought the rotating assy for the 496. took the money and bought a set of bare pro topline aluminium heads , having a long time local builder massage them and build them. he is talking me into a lower compression motor. 9.5 or so. trying to listen to wiser folks then myself for this engine. i just want to have loads of fun with it in the 65. been building all kinds of engines on my desktop dyno.looks like my bottom end will be over kill but thats all good if i end up bored and need more power right?
so anyhow looks like im heading to this combo
454 block with splayed mains
pro topline aluminium heads with 320 cc runners
single plane manifold with an 850cfm carb
4.25 inch stroke forged crank.
flat top forged pistons for a 9.5 static compression
6.385 rods.
obviousley i am still not sure about things like brands. oopen to everyones experiances.
thanks
again
greg

 

That is going to be a fun motor !! Do you want it to fit under the hood ? If so that makes your intake choices pretty limited. If not I would look at the Dart single plane and I would think very seriously about getting more carb. An 850 will work, but a bigger carb would certainly make more power, and not be any less steetable. If you want a bolt on carb that will run real well out of the box, and do not mind spending a few extra bucks for it, check out Pro-systems.com. More than a few guys run their stuff on this forum and he makes and tunes great carbs. I would go for at least a 1000 cfm or 1050 Dominator.

How big of a cam do you want to run? or better yet how much power, streetability, etc do you want out of the motor? A good solid roller or solid flat tappet would be the best choice for that motor. Something in the 250 at .050 range would be a good starting point for a high performance application. What kind of tranny ?

Depending on the cam choice I would run more than 9.5 to 1. What kind of gas do you get in your area? Even on crap 91 California gas most big blocks will run fine on 10 to 1.

 

That will be a fun ride! Have you decided on rpm range and cam type?

I agree w/ John, you can easily run 10:1 w/ aluminum heads -- and safely higher depending on valve timing.

These big engines loan themselves well to single plane intake manifolds. W/ 500" you won't be short on low end grunt. You're limited on single plane intake manifolds that will fit under a stock BB C2 hood. The Holley Strip Dominator fits and has a vacuum port for power brakes. I'm currently running an Edelbrock Vic Jr and had the carb pad milled at the same angle as the Holley in order to fit.

Don't skimp on carburetor flow. As John said above, these engines move a lot of air. A nice Holley HP 950 or 1000 should compliment your setup.

No personal experience w/ the Pro Topline heads, but they have a reputation for flowing very high numbers for a modest port volume.

Good luck on your project!

Take care,

Mark

 

I've got an aftermarket 70s type L-88 hood on it. i have a keilser tremex 5 speed and 3:90 rear end. i tried looking up pro systems and couldn't find any motor guys. got an address. gas here is petty good. in fact the local airport is about 5 miles away and i can just pull up to the pump and gas up on 100LLL (whatever that really means) i sometimes put in a quarter tank full. i'm undecided about the cam. i keep thinking about a solid flat or a roller hyd. i think i'd like to peak HP by 6500RPM at the latest . i'm looking for a highway hotrod not a real street warrior.

 

Were you unable to find Pro-systems web site ? try Pro-system.com
Since you have an L-88 hood and I assume you want the intake to fit under it, I would do what Mark did, get a good intake like a Victor Jr. and get it milled down. Remember you need room for an air cleaner too. Be sure to leave plenty of room for it to breathe. For more moderate street performance I would get an HP 1000 carb. I run one on my 625 hp 454 and it is a great carb. Get the annular booster model. My thoughts on the cam are the same, mid to high 240's at .050 on a hydraulic roller and high 240's on a flat tappet, maybe 250. I would stronly consider getting the cam on a 112 LSA, it really helps the street manners, makes a little less midrange, but in my opinion worth it due to the drivability through out the entire rpm range. The Tremec will help mask any loss of tq due to the slightly wider LSA.

As far as the max power at 6500 rpms, just for comparrison my 454 made max power at 6500 with a solid roller (255 and 262 @.050) on a 112. Ported oval heads, ported Victor Jr. and HP 1000. For your longer stroke you will need to run even more duration at .050 to make max power at 6500. In all honesty I do not think you need to build the engine to do that. Let that 4.25" stroke make some tq and shoot for max power at around 5800-6000. It will be a lot more "snappy" in the low end, and you will not have to rev the heck out of it

Your motor "may" be a little big for one, but the Edelbrock RPM dual plane (Air gap or not) is a great intake. I had one on my 454 for a while and it was a great street motor, VERY responsive with a solid roller of 242 and 248 at .050 and a Holley 850 flowed to 930.

 

Before you put any work into the heads make sure they are good castings. If they are a good set of castings, they are real good flowing heads. With Pro-Topline out of business there are a lot of "seconds" heads out there, espesially on e-bay because Top-line isn't honoring any warrenty claims so some dealers are dumping them out however they can. Pay close attenion to the intake port locations as there were a bunch of heads that had real bad core shift. Also watch for the machine work on the rocker arm studs as it was common for them to be drilled in the wrong location causing geometry problems.

Hope you got a good set, you will like them if you do.

 

got them from the local engine builder. he's got a real good rep, did a great job on my SBC stuff and is a good friend of one of my best buddys. Does a lot of work for him on bike stuff. he showed me the heads and seemed OK with them. (belive he said they came from vegas ) thanks for the tip though. i'll give him a call