Need Help With More Hp From 434 SBC

[want-a-be]

With the p-v clearances you have you can move the cam around a lil' bit. Advancing the cam will tighten up the exhaust and loosen up the intake clearances. This should help you on the bottom end but trim off your top end. Retarding it will tighten up the intake and loosen up the exhaust. This should help you on the top end. If you tighten up the LCA you will also tighten up those clearances. So if you opt for that make sure your cam manufacturer knows those numbers along with all your cam specs. Where are you installing the cam at?

If you're wanting to bump the compression a bit. I'd deck the heads around .014"-.015". This will knock 2 ccs out of the cumbustion chamber. But this will also knock that much out of your p-v clearance.

Could mark up your piston dome with a marker and dummy up the rotating assembly. Get the p-v at it's closest. From there you can take your valve and push it down to make contact on your piston and turn it a few times. You may be hitting somewhere that can be shave a bit in order to free up some clearance . If that happens then you can deck more. But...I wouldn't deck if you choose to run that cam. Might take .007 off just to true things up. I run a minum of .045" on the intakes and .095" on the exhaust. With .080" and .130" you have some room to move around.

The key here is to move your whole power band up 700 RPM and increase that multiplier. What rpm was your torque peak at and what was it?

Make sure you freshen up your valve job while you have things apart.

What Block are you running? Stock blocks won't make as much power as a good after market one will. How much vacuum are you running at an idle and in the RPMs. Gas porting might help you some with that. I can help you with that if you want.

How much access to a dyno do you have?

I have a ton more questions but this thing is long enough.

would be more then happy to help if you want/if I can.

Don

Ace Rod Shop

[killacamaro]

Originally Posted by want-a-be

With the p-v clearances you have you can move the cam around a lil' bit. Advancing the cam will tighten up the exhaust and loosen up the intake clearances. This should help you on the bottom end but trim off your top end. Retarding it will tighten up the intake and loosen up the exhaust. This should help you on the top end. If you tighten up the LCA you will also tighten up those clearances. So if you opt for that make sure your cam manufacturer knows those numbers along with all your cam specs. Where are you installing the cam at?

If you're wanting to bump the compression a bit. I'd deck the heads around .014"-.015". This will knock 2 ccs out of the cumbustion chamber. But this will also knock that much out of your p-v clearance.

Could mark up your piston dome with a marker and dummy up the rotating assembly. Get the p-v at it's closest. From there you can take your valve and push it down to make contact on your piston and turn it a few times. You may be hitting somewhere that can be shave a bit in order to free up some clearance . If that happens then you can deck more. But...I wouldn't deck if you choose to run that cam. Might take .007 off just to true things up. I run a minum of .045" on the intakes and .095" on the exhaust. With .080" and .130" you have some room to move around.

The key here is to move your whole power band up 700 RPM and increase that multiplier. What rpm was your torque peak at and what was it?

Make sure you freshen up your valve job while you have things apart.

What Block are you running? Stock blocks won't make as much power as a good after market one will. How much vacuum are you running at an idle and in the RPMs. Gas porting might help you some with that. I can help you with that if you want.

How much access to a dyno do you have?

I have a ton more questions but this thing is long enough.

would be more then happy to help if you want/if I can.

Don

Ace Rod Shop

Thanks for the response Don!I really don't think adding compression will help me from my research on this motor!I know I have a lot of clearance in the motor and I may tighten it up a little,but I had that in there for some safety(Motor has lasted me 8yrs)My peak tq was at 588@5100 and 669hp@6700. I run a Bowtie block and pull 12" of vacuum in RPMs! My last engine builder was so against Gas Porting!He says on the motors he tried this on,it always ate(scarred) up the cylinders quicker!However he said to do whatever I wanted! I am not a rocket scientist so I don't like to argue about something unknown to me!Is he correct?Yes i have a ton of access to the dyno(This motor in 8yrs has about 48 dyno pulls on it)Once again Thanks Don and all help is very appreciated!

[want-a-be]

I like the cushion you have in your p-v clearance. Thats the target(ish) I try for.

Where is your cam installed at?

Here is a Reher/Morrison site for some reading. There are some about gas porting. I'll let you decide. Also a good one about compression.

New Page 1

rmre start

rmre start

This will get you started. Theres alot of good reading there. Some of it supports what I'm saying. I've had some good teachers for building some hp. It wasn't R/M but they were Prostock champs a few years.

If you could post some pics of the domes of your pistons here I'd like to see them please. Before cleaning.

Thanks , Don

[MaxRaceSoftware]

Originally Posted by killacamaro

What's up Dusty!I thought about upping the compression but was told by several engine builders(Joe Sherman/L.Meaux) it wouldn't make that big of a difference in a 600-700hp motor.This is a nitrous motor so I couldn't tighten up LCA! I was thinking of going with a bigger cam and lighter(better) pistons.Tried a 1250 already with know luck!Thanks Dusty!

Here's a SBC Combination very similar to yours
that you might be interested in ? ? ?

and here's a Pic of a relatively stock 1987 Chevy S-10 Blazer



this SBC 434cid was installed in Danny Durand's 1987 Chevy S10 Blazer,
much sleeker and setup for DragRacing than that above Pic.

Danny's S-10 Blazer has custom paint job->
mainly Black, with shades of Yellow,Magenta,Green,Orange,and Silver
PowerGlide Trans 1.82 1st
4.86 Rear Gears
Marv Ripes 8" Converter
16x33 Slicks
3200+ Lbs w/Danny driving

No Problem Dragstrip , October 2007
Danny ran just on Motor , No NOS
9.440 ET and 142+ MPH best ET so far

on 200 HP NOS
ran 8.830 ET and 156 MPH

the 1987 Chevy S10 Blazer has a Frontal Area of = 29.112 SqFt
but in ET_Analyst , you use .80 to .85 % percent = 24.74 SqFt for input

here's the ETA Model




here's the SBC 434cid Engine modeled in PipeMax

[MaxRaceSoftware]

KillaCamaro and AutomotiveBreath,
you both might have seen Danny Durand's S10 Blazer run
a few Passes at No Problem Raceway ? ? ?


here's the actual Dyno Data on the SBC434




here's the Dyno Graph




here's the Dyno Test Description

[automotivebreath]

Originally Posted by MaxRaceSoftware

this SBC 434cid was installed in Danny Durand's 1987 Chevy S10 Blazer...

Danny's S-10 Blazer has custom paint job->
mainly Black, with shades of Yellow,Magenta,Green,Orange,and Silver
PowerGlide Trans 1.82 1st
4.86 Rear Gears
Marv Ripes 8" Converter
16x33 Slicks
3200+ Lbs w/Danny driving

No Problem Dragstrip , October 2007
Danny ran just on Motor , No NOS
9.440 ET and 142+ MPH best ET so far

on 200 HP NOS
ran 8.830 ET and 156 MPH

Larry,
I remember seeing the Blazer but didn't see it run. I really should spend less time
in the pits and more time watching, you never know what you're missing.

I have been following this thread, big CI small blocks are getting popular at NPR. Any
comments on KillaCamaro's 12.8:1 compression? Many of the 434's I'm seeing are
running the compression much higher.

[MaxRaceSoftware]

Originally Posted by automotivebreath

Larry,
I remember seeing the Blazer but didn't see it run. I really should spend less time
in the pits and more time watching, you never know what you're missing.

I have been following this thread, big CI small blocks are getting popular at NPR. Any
comments on KillaCamaro's 12.8:1 compression? Many of the 434's I'm seeing are
running the compression much higher.

i'm a Compression Ratio "Freak"

either i misunderstood KillaCamaro's CR question
or he misunderstood my answer ?

i definetly don't remember advising him
that there would be no more HP and TQ to gain
from increasing CR !!!

i would advise him to run at least 14:1 CR and upwards

we've tried as high as 16.7 to 16.8:1 on Craigs A/ND
and we currently run 16.2:1 CR on Jeff Colletta's NPS BBC632 1322HP / 1640's on Legal NOS jet

Video of Jeff_Colletta_BC632_1316-HP - Photobucket - Video and Image Hosting


---------------------------------------------

both our SBC434's are'nt too far away from each other in Part's Specs,
but i'm wondering why Killa's 434 is Peaking so low in RPM ??
with the same Dart Pro-1's ?


it seems there's a severe CSA speed problem !

the Dart Pro-1's on Danny's 434 are the best i can do
without welding pushrod areas up + widening the pushrod pinch.
We're making Peak HP @ 7500 and Peak TQ @ 6300 RPM

there's more HP there welding those Heads
and on Dany's 434 it really need a pair of larger Headers,
but we used what he already had.

[automotivebreath]

Originally Posted by MaxRaceSoftware

both our SBC434's are'nt too far away from each other in Part's Specs,
but i'm wondering why Killa's 434 is Peaking so low in RPM ??
with the same Dart Pro-1's ?

it seems there's a severe CSA speed problem !

You're thinking the air speed is too high at the push rod pinch? What CSA are you
getting at the pinch with out welding and widening?

[MaxRaceSoftware]

Originally Posted by automotivebreath

You're thinking the air speed is too high at the push rod pinch? What CSA are you
getting at the pinch with out welding and widening?

i didn't mean for anyone to think i wasn't widening the Pushrod Pinch,
i'm "maxing-out" that area...its just i didn't weldup Danny's Dart Pro-1's
and widened that area even further !

i'm going as far as i can enlargeing the Pushrod Pinch
"without" resorting to offset Rockers/Lifters and without Welding or Epoxy.

i've made myself a few Custom metal thickness checkers about 30+ years ago,
and they work great as you never breakout thru pushrod sides
and if your careful you can maintain wall thickness in that area to around
.040" ...then you attack the Port's Center divider wall for the rest of the CSA.

But i'm also sure Killa's has a speed problem on the Short Turn Curve
and in the Transition from the Bowl to the Chamber as well
for the HP and RPM point to be so low.

if i plugged in the Data into PipeMax it wouldn't Model his Engine correctly,
it would show its no where near accessing the FlowBench Flow he has.
That's the first Tip-off there's a CSA speed/Choke problem(s)

[automotivebreath]

Yes I understood that you did what you could with in the constraints with
out cutting through and going the offset rocker route. .

I did a set of 215 pro 1's with a 2.05" valve for a 355 a while back. Long story short the
bottom end broke and the heads ended up on a 434 much like whats being described
here. Everybody said it wouldn't run because of the heads but surprisingly it's been
9.4's, it says a lot for the little darts. To put things in perspective, the car weighs 2800
lbs and is fairly aerodynamic; so I'm sure he's leaving plenty on the table.

Anyway I'm telling him he needs to get the heads redone, I reading up on this to see
what others are doing, I'm all ears. I see your getting some impressive numbers,
especially when you consider the size shape and weight of the Blazer.