Help me to get more power!

jez · Posted: Thu Aug 16, 2007 12:26 am Post subject: Help me to get more power!

Now, talking about my engines power potential, what do ya think?
A larger cam + matching intake& carb. How much power can I gain?
Let's say Comp XE268H + roller rockers + Edelbrock performer RPM + Mighty Deamon 750

Right now the spec are.

350 cid SBC

Flowtech headers
Holley aluminium intake (old low rise stock replacement) gasket matched
Holley 600 cfm (not running very good)
Full ported double hump heads (1.9/1.5)
MSD HEI kit
MSD 8.8 wires
Electric fan
H-pipe with unknown loud mufflers
50-2434 cam from Chevy standard hydraulic lifter cam with an intake lobe of 282 degrees advertised duration at .465 lift and the exhaust id 292 duration and .488 lift--intake lobes are on a 109 degree center and the exhaust is on 119 degree centers. @0,05" lift duration is around 106/116

th350 with shift kit
2.73 rear with full lock
275/60 R15 tires

I was runing 14,8 @ 97 mph with this setup..
It is about 275 rwhp.

Snaggle To0th · Posted: Mon Aug 20, 2007 6:08 pm Post subject:

Sounds close to the the same set up my friend witha 72 nova had before he went with a better cam and bored the engine out .030" and was running low 14's. I say if your going to be using Edelbrock get the matching parts to go with it. I say 750CFM is pretty large for what you have go wiht the max of a 650CFM. Buddie with the Nova was using a 625 on the current set up and was pulling mid 13's switch the carb out witha 650cfm and now runs low 13's. Plus he now has slicks better suspension set up and higher rear gears and dips into the 12's now.

-Anduh
_________________

Proud Wyotech Graduate

Reazon · Posted: Mon Aug 20, 2007 7:14 pm Post subject:

First question do you have a stall converter? That will add performance. Also you rear gears is low you upgrade that and you will take a lot of time off of you 1/4s. Your cam choice is good. Might even want to bump the size up a little more.

Snaggle To0th · Posted: Tue Aug 21, 2007 12:01 am Post subject:

A stall converter wont give you extra power, it'll allow torque converter to start transfering torque through the drive train at a higher RPM, which your cam is designed for. Having a mismatched stall speed and cam shaft can create powerloss through the drive train and power train.

-Anduh
_________________

Proud Wyotech Graduate

jez · Posted: Thu Aug 23, 2007 5:29 am Post subject:

I'm going to mach converter to other things, 2000-2200 should be ok.
And yes, 750 is too big, 650 Mighty Deamon fits better!

mnunn · Posted: Sat Sep 01, 2007 7:43 pm Post subject:

It sounds to me like the cam's a little too large for the heads and manifold. Or conversely, the smallish valve heads and stock manifold are too small for the cam.

I agree that a stall converter and a lower rear gear will help you better apply what you have today. But if you want the engine to produce more, I'd take a strong look at the heads and manifold.

I once had a set of 1.94 camel humps on my 68 Camaro. They were nothing special compared to today's better breathing heads (Just don't trade down in the compression ratio dept.).

JMO.
_________________
70 Elky (Non-SS) 454CID, TH700-R4
69 Chev C-10 Pickup (recently Upgraded to 454) w/TH400
29 Model A (Recently Sold).

jez · Posted: Thu Sep 06, 2007 7:10 am Post subject:

At first I'd like to know what are my heads capable of.
If I can't get more than ~375 hp @ flywheel, going to purchase new ones.
What do you think, is it possible?

Mama Mayhem · Posted: Thu Sep 06, 2007 12:40 pm Post subject:

To answer that we need to know what heads you have. If they're Chevy production heads we need the casting numbers to get an idea.
_________________
Mama Mayhem's Gallery
I'ma going to EL
15.610 @ 90.31mph 9/8/06

jez · Posted: Thu Sep 06, 2007 1:39 pm Post subject:

Heads casting number is 3973370. 64 cc.

Edit: I add some pictures of porting before 3 angle valve job and inserts.

Mama Mayhem · Posted: Thu Sep 06, 2007 2:41 pm Post subject:

According to Mortec those are 69-70 64 cc, 350, sold over the counter in the U.S., on production 350/300 hp Pontiacs in Canada and straight or angle plugs. Any idea on the intake cc's? Not gonna flow as good as Vortecs, but should still be decent. Double humps were good in their day, but that was 30 years and more ago.
Best breathing heads for the money these days are Vortecs, the standard production are only good for .480 lift max, but these CLICK HERE are good for .550 lift out of the box are are drilled and tapped for screw in studs. Matched up to a dual-plane low to mid-rise Vortec manifold, you'll have more torque that you'll know what to do with.
_________________
Mama Mayhem's Gallery
I'ma going to EL
15.610 @ 90.31mph 9/8/06

mnunn · Posted: Thu Sep 06, 2007 7:28 pm Post subject:

Chevyhiperformance.com did a SBC and BBC head "bakeoff" a while back, but I went to their tech articles and couldn't find the flow numbers for your heads. Maybe you'll have better luck.

Below is a review I found at ChevroletNova@groups.msn.com. I tend to agree with the author. Even though it doesn't answer your horsepower question directly, it's still very encouraging, especially if those beautifully ported heads have the 2.02 intakes.

A 327 with the 2.02 version of these heads could get 325 horsepower (1 HP/Cube), so if yours have the 2.02" intakes you should be able to get upwards of 350 HP without much more than 10:1 compression, a solid roler cam and a good, balanced rotating assembly.

If you want 375HP or more from a 350, then I think you'd be pushing the head's capacity a little. I'd probably opt to sell these heads to a collector and go with the better flowing Vortec or aftermarket aluminum heads like Edelbrock, AFR, etc.

Here's the quote:

"3973370" – A good over the counter head. They had 64CC combustion chambers, supposedly straight or angle plug configuration. Used a set of these on all 3 of my 383 strokers, they originally came with 1.94/1.50" valves. We did some major port massaging and installed 2.02/1.60" valves, they responded very well to the modifications and worked very well. The combustion chambers were 64CC's. These were a decent iron head, with a lot of potential for performance."
_________________
70 Elky (Non-SS) 454CID, TH700-R4
69 Chev C-10 Pickup (recently Upgraded to 454) w/TH400
29 Model A (Recently Sold).