Where to go next? Low 11's high 10's??

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jbharris

jbharris

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So I wanted to make one more trip to the track. My 340 said that's enough and started crying in the trailer. Well leaking that is. I found two freeze plugs leaking and of course the one is in the back of the block. I was hoping for one more year out of the 340 but it has to come out now. So my question, what would you do? I'd like to step the car up some but not kill my bank account. My car is a 68 Valiant. It was a street car but slowly has become a track only car. Its pretty consistent running anywhere from 11.90-12.50 depending on the track and how hard I run it. It's a basic 340 out of the box edelbrock rpm heads comp soild cam 244/525. 750 carb M1 intake and MSD dizzy and box. 904 with 3500 PTC convertor and 4.30 gears. Gaged, frame tied and mini tubbed
I'd like to see the car run low 11's or even break into the 10's What would be the best bang for buck upgrades I can do?
 
cylinder head rework? re-ring and bearings. new valve springs, maybe beehive and retainers. such a question just snowballs the possibilities of what to do.
 
abdywgn said:
cylinder head rework? re-ring and bearings. new valve springs, maybe beehive and retainers. such a question just snowballs the possibilities of what to do.
Click to expand...

I know possibilities are endless. Just putting it out there. I agree the head work would be a big plus. I was already planning on freshening the short block up.
 
that 4.30 is probably getting you on the top end a little, what's you wheel/tire set up? Shocks?
 
Exact compression ratio is?
Car weight?
What is your finish line RPM?

I don’t know what you consider breaking the bank on expenses is. Would head porting be out? Or sell the stock Edelbrock heads to roll over into a set of Trick Flow heads.
That Comp Magnum cam could use more lift on it. It would bring lift to .560 before lash.
Any fiberglass in use?
Full interior?
 
rumblefish360 said:
Exact compression ratio is?
Car weight?
What is your finish line RPM?

I don’t know what you consider breaking the bank on expenses is. Would head porting be out? Or sell the stock Edelbrock heads to roll over into a set of Trick Flow heads.
That Comp Magnum cam could use more lift on it. It would bring lift to .560 before lash.
Any fiberglass in use?
Full interior?
Click to expand...

Compression is 9.5.1. But I don’t know that to be exact.
Never weighted the car. It’s only missing the back seat and heater box. The bumpers are fiberglass.
Bracket racing the car I’ll shift it at 5500 and see 6000 though the trap. If I bump it up to 6500 I see 5800

I kind of thought the car could be bigger.
Are the trick flow heads that much better out of the box?
 
With all you have if any changes are in order I’d be doing a cam swap, something quite a few steps bigger for sure, and a converter to go with it. Keep everything else, just freshen the rest up. Work on the intake plenum and runners if not already done, lose some more weight if possible.
 
Assuming the race weight is in the 3200lb range, to go from 11.90’s down to 10.90’s...... you’re looking at needing about 110-120hp more than you have now.

If sticking with a stock stroke 340, that’s going to require a pretty substantial change to the overall combo.

Personally....... I’d be saying “hello stroker kit”.
 
150 shot of juice...
Screenshot_20200325-084917.png
 
PRH said:
Assuming the race weight is in the 3200lb range, to go from 11.90’s down to 10.90’s...... you’re looking at needing about 110-120hp more than you have now.

If sticking with a stock stroke 340, that’s going to require a pretty substantial change to the overall combo.

Personally....... I’d be saying “hello stroker kit”.
Click to expand...

That empty 360 block in the corner is calling
 
You don't need it for long only about 9 seconds LOL, anything you do to make that kind of improvement will take modification and changes $ I just think for the money and it's still one of your best options. Just my two cents.
 
But if working with what you have and the power adder is off the table,I would be looking at raising my compression to around 11 .1 via head surfacing along with head porting
and more rear end gear 430ish I would think you would be there.
 
I think the guys are right in the 3 choices shown.

N02
Stroker
Or
What I call the “Mr. Cooke’s 5 C” program. Which consists of;

Cam
Carb
Compression
Converter
Cogs (AKA Gear ratio)

Now it’s down to the 2 silent “C’s” in which it oh probably have the “cohonies” (balls) for faster but do you have the “Cash?”

All avenues above are good ones.
I like the call of the extra 360 block in the corner myself.

OH! I forgot... the Trick Flows flow a little more than most well done Edelbrock heads. So yes. I also have a set. Excellent S/S head.
 
3 things I'd do :
  • I'm assuming you have a 9.5" converter. If so, going to a 8" would help you, especially if you are just bracket racing it.
  • I would add more cam, but I wouldn't get crazy.
  • Mild porting on the eddies.
  • My thought is more cam, more converter, and mild porting along with a freshening up would get you low 11's.
 
Thanks for the input guys. I agree 150 shot would be the cheapest but the nostalgia group I race with has a no nitrous rule.
So it’s between building the stoker or freshening up the 340 add bigger cam, head work and converter.
I’ll have to start figuring out the 2021 race car budget.
 
jbharris said:
Thanks for the input guys. I agree 150 shot would be the cheapest but the nostalgia group I race with has a no nitrous rule.
So it’s between building the stoker or freshening up the 340 add bigger cam, head work and converter.
I’ll have to start figuring out the 2021 race car budget.
Click to expand...
Your group needs to get their nostalgia correct.. they've been using nitrous and drag cars since the early sixties and probably before that... So I assume they don't allow blowers or turbos?...
 
jbharris said:
Thanks for the input guys. I agree 150 shot would be the cheapest but the nostalgia group I race with has a no nitrous rule.
So it’s between building the stoker or freshening up the 340 add bigger cam, head work and converter.
I’ll have to start figuring out the 2021 race car budget.
Click to expand...
NOS is cheap at first, but if you are a weekend warrior bracket racer, the cost gets out of control. If you can keep it on pump gas, that would be best in my opinion.
 
j par said:
Your group needs to get their nostalgia correct.. they've been using nitrous and drag cars since the early sixties and probably before that... So I assume they don't allow blowers or turbos?...
Click to expand...
Nothing more boring and unimpressive than cars running down the track on nitrous, I’d just walk on by them in the pits and head for the cars that do it on motor alone........just sayin:poke:
 
jbharris said:
So I wanted to make one more trip to the track. My 340 said that's enough and started crying in the trailer. Well leaking that is. I found two freeze plugs leaking and of course the one is in the back of the block. I was hoping for one more year out of the 340 but it has to come out now. So my question, what would you do? I'd like to step the car up some but not kill my bank account. My car is a 68 Valiant. It was a street car but slowly has become a track only car. Its pretty consistent running anywhere from 11.90-12.50 depending on the track and how hard I run it. It's a basic 340 out of the box edelbrock rpm heads comp soild cam 244/525. 750 carb M1 intake and MSD dizzy and box. 904 with 3500 PTC convertor and 4.30 gears. Gaged, frame tied and mini tubbed
I'd like to see the car run low 11's or even break into the 10's What would be the best bang for buck upgrades I can do?
Click to expand...
Best bang for buck, find some weight & pull it out.
 
12many said:
Nothing more boring and unimpressive than cars running down the track on nitrous, I’d just walk on by them in the pits and head for the cars that do it on motor alone........just sayin:poke:
Click to expand...
It's okay most people are scared of what they don't know about....:D..
 
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