Better acceleration?

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Slugfarm

Slugfarm

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So I was finally able to get my Valiant out for a real road trip for the first time since the rebuild, and really since the first time since I've owned it. We had a blast, running about 650 miles on mostly paved and some gravel highways and roads in the Oregon Cascades mountain range. Dry clear weather, mild temps. around 4000' elevation average. The motor purred like a kitten (well, a kitten with solid lifters anyway), comfortably cruising 75mph at around 3000rpm. Good mileage, no leaks at all.

I had real issues with climbing moderate to steep grades and with acceleration in general. So I'm wondering what I can do to get- what, more power, or more torque, or whatever- especially at higher rpms. I run a 225 with a Holley 390 4bbl carb, slightly larger cam, Clifford intake and headers, 2.5 single exhaust, and, yes, a manual 3-speed stock 1965 transmission. Thanks in advance!
 
CR and head flow AKA Porting/valves, the stock /6 head is the biggest roadblock to power.
 
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The head was milled .001 but no port work yet. Not sure what the tear end in but am pretty sure it’s stock base level 1965 for the original 170 engine.

I’d probably go supercharger over turbo if I had the cabbage, just because I’m a little old school. But either would probably mean new everything past the crankshaft, so no.
 
Slugfarm said:
The head was milled .001 but no port work yet. Not sure what the tear end in but am pretty sure it’s stock base level 1965 for the original 170 engine.

I’d probably go supercharger over turbo if I had the cabbage, just because I’m a little old school. But either would probably mean new everything past the crankshaft, so no.
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.001" is ONE THOUSANDTHS of an inch. I hope you mean .100". That's a good start. If the engine was a 170 originally and with a three speed manual, very likely it is like mine and has a 3.23 gear. Mine accelerates STRONG in high gear up inclines and I don't even have to THINK about down shifting. What kind of ignition and ignition curve are you running? Also, did you degree the cam?
 
Driving up the cascade mountain range is a lot different than driving up some inclines in Georgia. I’d get a Torqstorm supercharger if I was wanting to keep the slant 6.
 
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Dartsun said:
Driving up the cascade mountain range is a lot different than driving up some inclines in Georgia. I’d get a Torqstorm supercharger if I was wanting to keep the slants
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When you start seeing the run away truck off ramps you know your in the mountains.

The grade in and out of Maupin and Cabbage Grade outside of Pendelton are some steep suckers.
 
RustyRatRod said:
What kind of ignition and ignition curve are you running? Also, did you degree the cam?
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I didn’t do the rebuild myself and don’t know the answers to these questions. But I should be able to find out from the builder, right?
 
First off; 75mph at 3000 rpm points to 3.23gears with about 24" tires.
Your problem is not gears, rather it is the 4000 ft; and you can't do a darn thing about that. If you want to keep that engine, you will need to super/turbo charge it, as per posters 4 and 7 who are are right on.
Else get a bigger engine ......

The optimum pressure for best gas is about 165psi, which in your 225, with a stock cam or any cam with an Ica of 48*, happens at 9.0 Scr at sealevel.
By 4000 ft, the pressure is down to 143psi, according to the Wallace Calculator. That is a loss of 22psi and is the equivalent of, running;
at 8.0 Scr at sealevel, or
at 8.3 Scr at 1000 ft.
Only a turbo/super charger can pump that pressure back up; or a purpose built 9.9 Scr 225engine, that you better not try to drive at any lower elevation.
 
Slugfarm said:
So I was finally able to get my Valiant out for a real road trip for the first time since the rebuild, and really since the first time since I've owned it. We had a blast, running about 650 miles on mostly paved and some gravel highways and roads in the Oregon Cascades mountain range. Dry clear weather, mild temps. around 4000' elevation average. The motor purred like a kitten (well, a kitten with solid lifters anyway), comfortably cruising 75mph at around 3000rpm. Good mileage, no leaks at all.

I had real issues with climbing moderate to steep grades and with acceleration in general. So I'm wondering what I can do to get- what, more power, or more torque, or whatever- especially at higher rpms. I run a 225 with a Holley 390 4bbl carb, slightly larger cam, Clifford intake and headers, 2.5 single exhaust, and, yes, a manual 3-speed stock 1965 transmission. Thanks in advance!
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I would start with the timing. What's the initial timing and What's the total and then after that I would go to the transmission kick down perhaps or how it's programmed meaning the valve body and if it's been shift kit'd or not. A real killer for any combination is having an automatic transmission that isn't programmed right. If it will not kick down when you need it to it'll just be a ******* dog
 
Does a supercharger necessarily require upgrading the rear end, transmission and/or cooling system?
 
Slugfarm said:
Does a supercharger necessarily require upgrading the rear end, transmission and/or cooling system?
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Supercharger is a little extreme if all your looking for is a bit more power for going up hill, now if your looking for general performance like better 0-60, 1/4 mile etc.. than supercharger would be a good way. With 10 psi your probably be 250-280hp so rear end yes, trans should be fine maybe better clutch, cooling maybe.
 
273 said:
Supercharger is a little extreme if all your looking for is a bit more power for going up hill, now if your looking for general performance like better 0-60, 1/4 mile etc.. than supercharger would be a good way. With 10 psi your probably be 250-280hp so rear end yes, trans should be fine maybe better clutch, cooling maybe.
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You know how it is - I'm always looking for more/better/faster:p.
 
The trick or the problem gaining any huge amount of NA power at low rpms is it's very hard.
Eg. take multiples of 1313 rpms so 1313/2626/3939/5252/6565/7878 etc.. hp percentage for every lbs-ft goes up, 25% for each step up of 1313 rpm 25%/50%/75%/100%/125%/150% gain for every torque gain in those rpms. So a gain of 10lbs-ft at each oh those rpms would be a gain of hp = 2.5/5/7.5/10/12.5/15hp at each etc.. And your engine probably making most amount of torque it can NA 3000 rpms and under and even if you could gain huge amount of low end torque the hp gain % of torque is relatively small at those rpms anyways plus the main way to gain torque is displacement, natural and or artificial.

So the trick is to increase 3000-5500+ rpm torque without hurting/altering the low end street driving rpm/torque of under 3000 rpms. since you already done basic hot rodding carb cam exhaust etc.. just leaves head now if you can port it out then it's a worth while mod but if you got to pay someone else money would be better spent on a blower since it will gain everywhere, if you can do both even better, blower multiples engines NA power.
 
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Dartsun said:
Driving up the cascade mountain range is a lot different than driving up some inclines in Georgia. I’d get a Torqstorm supercharger if I was wanting to keep the slant 6.
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Well of course, but he's describing a total dead dog. Even in the mountains, a well tuned slant 6, especially a 225 will have "some" torque.
 
RustyRatRod said:
Well of course, but he's describing a total dead dog. Even in the mountains, a well tuned slant 6, especially a 225 will have "some" torque.
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What the problem is is we get used to driving our new cars.. The question might be what does the op drive or has he driven on a daily basis??.. . Because if it is something like my wife's Kia, it would smoke that /6 up any hill...
 
any body dont think georga ant got some steep mountains ant ever been north of hot'lanta!! theres stuff up there make ya knuckles white even in lower gears!! up above dawsonville back over to hiawassie!!! high altitudes needs high compression and timing,..is cam degreed in or dot'ed up? needs to be degreed, and maybe advanced a few degrees!
 
A nice upgrade (if you can afford it) seems to be a Torque Storm supercharger. I don't have one and no personal experience, but a friend has one on a 1968 Dart. The car has extensive mods other then the super charger, but can run high 12's in the 1/4 mile, and gets 20-24 mpg. He actually drove the car close to 1,000 miles each way from home to the drag strip and won the races on sat and sun.

Slant 6 – Single Charger Kit | TorqStorm

Complete kit will mount one TorqStorm® Supercharger to a 1960-1984 Slant 6 engine.
torqstorm.com torqstorm.com
 
Charrlie_S said:
A nice upgrade (if you can afford it) seems to be a Torque Storm supercharger. I don't have one and no personal experience, but a friend has one on a 1968 Dart. The car has extensive mods other then the super charger, but can run high 12's in the 1/4 mile, and gets 20-24 mpg. He actually drove the car close to 1,000 miles each way from home to the drag strip and won the races on sat and sun.
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This sounds exactly what I'd like to have. Used an app yesterday on my phone and figured out I'm high 12's in the 1/8th mile, which doesn't make me like driving the car any less, but would be nice to have a bit more oomph... Do you know any of the other details of what was done to the car other than the torqstorm?
 
rich_mc said:
This sounds exactly what I'd like to have. Used an app yesterday on my phone and figured out I'm high 12's in the 1/8th mile, which doesn't make me like driving the car any less, but would be nice to have a bit more oomph... Do you know any of the other details of what was done to the car other than the torqstorm?
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I'm not sure about eveything. Don't know the CR or what particular cam. It does have FI, and one of the Megasquirt computers. The iceing on the cake is a GM 200R4 transmission. 4speed OD with a higher stall lockup converter. He is on slantsix.org as dart270
 
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