Need Advice.....Marv? Super73?

[sav300]

I've asked many questions and read many posts on many forums, but now I've taken the time to work out the bugs on what I really want(Reality). Here is what I'm looking to get out of my hauler.

Good manners on the street with easy drivability, no excessive cam or giant stall, and healthy numbers that will allow me to hold my own at the track.

The motor has plenty of room to grow and this is what it currently has in it:

350 Bored .030 over
Forged Scat 6" rods
KB pistons (rated CR is 10.65 with 64cc heads)
Edelbrock Performer air gap intake
Edelbrock Performer cam (420/442 lift 204/214@050)
Proform Full roller 1.6 rockers
MSD ignition with all the goods
Melling high volume oil pump
ARP studs everywhere possible
Stock 305 Port and Polished heads
Stage 2 Jet rebuilt Quadrajet
Electric fans
Headman headers (1 5/8" primaries 3" collector)
2 1/2" exhaust before the tire with Flowtech After burner mufflers
And nothing, but an alternator

This all made 252HP and 320TQ at the wheels traveling through a TH350, HO72 rear end with 4.56 gears, and 33" tires in my 3/4 ton 70 Chevy. It is begging for more air as it peaked at 4900RPMs, the valves float at 5200RPMS.

I was looking at the Comp cams XE274H cam, ProComp 190cc aluminum heads(64cc chambers with 2.02/1.60 valves and dual springs good for .550 lift), Schoenfeld headers (1 3/4 primaries with 3" collector), 2500 stall converter, built TCI or B&M TH350.

With my gearing I will benefit from a cam that builds power in the higher RPMs. What I'd like to know is do you think there is any thing else I should do? Aftermarket oil pan with crank scraper, high flow water pump, etc.? Does my expectations and list sound reasonable?

Thanks for the help and input,

Thomas

[Super73]

TH350, 4.56 gears, and 33" peaked at 4900RPMs, the valves float at 5200RPMS.


By these figures (5k rpm) assuming 5% verter slip, this would only net you 102.3mph to work with. With that alone, it's going to be hard to go faster than a mid 13 with an optimized set up. With 252hp I figure your really only going to get to a low 14 assuming you are 3,800ish race weight.

I would bet that with just the head swap you would pick up both RPM and power. I don't think you'll pick up a lot with just heads, but probably 5-10% in both catagories if I had to take a guess.

The cam is definately going to move your RPM up with the mentioned heads. How much is really going to depend on where you position the cam in the motor, and the rest of your valvetrain.

I'd see what happens with your existing headers before you swap them. This way when/if you swap you can decide what was better for you.

Do you have a factory verter now?

[sav300]

Originally Posted by Super73

[I]Do you have a factory verter now?

Unfortunately I do and it kills me off the line even with the 4.56 gearing. The transmission is also pretty much stock and it has some slippage in 3rd gear that is noticeable.

The heads will help alot and I'm just trying to work with what I have. I love the strength of the HO72 and I'm stuck with that gear ratio. I will run the same headers and see what happens. Is there anything else that might help my situation? And is there anything you would do differently? I'm open to any and all opinions and suggestions.

Thanks

Thomas

[sav300]

And would anyone run a different tranny? I've thought about droping a 4 speed auto in it, but I'm not too confident in their strength and durability unless you drop $2500+ into them. Also considered and manual, but I've always been an automatic guy.


Thomas

[Super73]

Since I am looking at shaving weight and getting more serious about track only, my 4L80E is for sale with verter. This is a auto 4 speed with lock up converter. It handled everything my little 347 could throw at it plus a 100hp hit. There are companies that make manaul valve bodies for them like transgo and you would not need an additional electric trans box for the shifting. Lock up can still be achieved with a sitch to the trans harness.

At 65mph with 4.56's and a 30" I sit at 2,450 rpm..

I would not run a 60E.

Let me know if you have interest in it.

[Marv D]

Originally Posted by Super73

.......

I would bet that with just the head swap you would pick up both RPM and power. ...........

Not to diminish any other comments and discussion Super is talking about here. but I am going to harp on this ONE topic just a bit.

One of my pet-peeves is the 305 heads on a 350. It's good for compression and low speed power,, like for a fuel injected a rock crawler idling along at 400-500rpm,, or a street motor that seldom sees the high side of 3000rpm, but I've never seen any combination at the track with any 'tricked out' 305 head on a 350 that impressed many..... well,,,, unless there was a big-ass turbo forcing air through those small ports and valves.
This is totally evident with your 4900rpm peak. That's about right for torque, but even a poorly built small block will EASILY make good horsepower to 6000-6500. True that there usually all done around 6500 without building a real animal, but power to the mid 6000 range is the NORM. Even the Edelbrock, old Holley systemax packages, and most every other mail-order package will have a HP peak well into the 6000 range. 400ish HP,,6000rpm, it's all as easy as picking up the phone and offering up your first born (or a credit card) these days.

Think of it this way....... Plain and simple. There is only one way to make power,, burn fuel. You can't just dump raw fuel in the chamber, you have to have the right amount of oxygen for it to burn. Be it chemical (N20), forced induction to stuff more air in the chamber, or normally aspirated! You HAVE to have the proper amount of air with that fuel. If your doing it N/A.. you have to move more air to make more power. The really good thing here is the internal combustion motor is nothing but a BIG-ass air pump. That's really all it does is move air (with fuel) in, use it's energy to push on pistons, then expel the waste air out the exhaust port. How simple can it be... put MORE air in,, push harder on the pistons! Expel more waste gases. So,,, only thing you need to do is look at where is the inhibiting factor in YOUR combination?????

So have I made my case for taking them 305 heads, bolting a chain through the rocker studs, and making 'proper' use of them beside your fishing boat????

A combination can be a 'fluke' of parts and pieces that happen to fall together in one car and is a stellar performer, or a scienced out project that never realizes the potential we thought it 'should have been'. But one thing for sure, the place to start building a motor combination is to pick a head that will support the power level your seeking. If your thinking about power adders at all, I'd leave that to the great advice of those around here more knowledgeable about it. But if it's a N/A combination. START by picking a head that will support your goals.

Just be aware,, a head that fits your budget, may not fit your goals. IMO it's the most important piece of the package and is worth waiting, and saving for.

(OK, rant off)

[Super73]

Originally Posted by Marv D

Not to diminish any other comments and discussion Super is talking about here. but I am going to harp on this ONE topic just a bit.

Man, at first I thought I was going to get yelled at for suggesting power and RPM would increase with a simple head swap.. Now I see that Marv is actually agreeing with me..

[Marv D]

LOL at getting yelled at. To me mentioning the 305 heads on a 350 are very similar to the finger-nails on the chalk-board thing,, or.... my wife in a full PMS screeeeech!!

[sav300]

Originally Posted by Marv D

LOL at getting yelled at. To me mentioning the 305 heads on a 350 are very similar to the finger-nails on the chalk-board thing,, or.... my wife in a full PMS screeeeech!!

Well apparently I know how to get your attention!! I understand what you are saying about the 305 heads and I can't agree more (I've obviously seen the effect first hand). The main reason I put them on was for the compression and the torque. But stuffing 6" rods in it then toping it off with 305 heads just doesn't work and even I can say that it kind of defeats the purpose to put in those rods.

So with that aside I will say, yes its was a terrible move, but thats why I'm going to install the heads that I originally based the engine off of. But before I did I wanted to make sure that I had input and (maybe??) some approval from those that have more experience with heads and high RPM's.

Thomas

[cableguy0]

305 heads on a 350 is kind of like unplugging 2 ignition wires and expecting a good result.Having more compression means NOTHING when the heads cant flow any air, Its definately counter-productive. Get some heads on there. Dump that performer cam for something more modern. Look at either the comp xe line or the lunati voodoo line. The edelbrock cams are just reboxed generic grinds and while they work well your paying an extra 100 bucks to have them show up in a box that says edelbrock on it. Decide on what you can afford for heads then we can steer you right on a cam.

[Marv D]

Thomas, I don't know what heads you built the combination around, but something I will offer. I bought a used set of the old AFR 210s, ran them for 3 years and was lending them to a buddy while he builds his 'dream' engine. I decied to take them to my machinist and get them freshened, Decided WTF,, while there and apart, lets spend the $70 to get a flow sheet from a reputable SuperFlo bench on a set of BOX STOCK raceready (not the cnc version) AFR 210 heads.

I've always loved AFR for their honesty in advertised flow. here's the report

@ .2 125cfm
@ .3 180cfm
@ .4 231cfm
@ .5 269cfm
@ .6 287cfm
@ .7 286cfm
@ .8 287cfm

Obvious knee in the flow is at .60

Now remember these were the old 2002 version of the 210 'race ready' package. Todays 210 'eliminator' head is slightly improved and advertised as
.2 139
.3 199
.4 249
.5 279
.55 289
.60 295

That's pretty close being flowed and matching +/- 1.5% from advertised. I sure wish EVERY head manufacturer out there was as close!
Point I'm getting at,, AFR 210 would be a nice head to build around for a upper end street motor with around .55 or .65 valve lift,, or a formidable bracket motor to take a 3500 pound brick into the 10's with enough compression, cam and rpm. I'm using this set on a buddy's 406 with a fairly mild hydraulic roller for a little street small block with balz. I thouroughly expect him to be booted for running 10's without a bar in his 66 Chevy II.

ONLY thing I will say. The alloy AFR uses is the aluminum welders NIGHMARE. I had a set repaired after an major engine explosion and the machine shop could not get a good weld. So they sent the head to a shop specializing in welding aluminum. The head came back beautiful, but the shop told the machinist they didn't EVER want to patch up another set of AFR's. The stuff must be horrible to weld. Don't know why,, just saying if you hurt a set of AFR's find a GOOD shop to do the patching.

[Super73]

I'd still put a .700 lift cam with those heads.. Why, more duration spen at .600

[sav300]

Well Marv, the heads I built the engine around are a rebuilt set of ProComp Aluminum heads that have some machining done to them. They have 190cc intake runners, 64cc chambers, 2.02 intake, 1.60 exhaust with titanium valves, and dual valve springs that are good for .550 lift.

I know you like the AFR's, but I figure you might have some input.


Thanks,

Thomas

[Marv D]

Titanium valves and only .55 lift????? You looking to spin 9000+ or something???? Heck the valves are probably worth more than the heads!!!! (LOL)

And I'm with you super. Those heads don't even wake up till .4

[sav300]

Originally Posted by Marv D

Titanium valves and only .55 lift????? You looking to spin 9000+ or something???? Heck the valves are probably worth more than the heads!!!! (LOL)

And I'm with you super. Those heads don't even wake up till .4

Well they come from the factory with stainless valves, but aparently the guy that has them thought he needed better valves than that. High rpm 327's were his specialty and he was damn good at it.

I originally built my engine based off of the stock ProComps, but these heads have some work put into them! I'm not sure if those valves will remain in there when he gets rid of them, but thats a heck of a deal if they do. Either way thats what I will run whether I get the already machined heads or a set of factory ones and have them machined.


Thomas