How much HP do I need for easy passing at 60mph?

[Beatcoaster]

I am looking at swapping in a new engine or rebuilding the tired 307 in my 69 long bed. I used to have a Subaru STi that would run 13.0 in the 1/4 all day long, not fast by any means, but great fun on the street. I absolutely loved the passing power it had, and it was put to good use lots as we have some property on the other side of the mountains. We make 2-3 trips a month, and the roads are single lane highways nearly 3 hours of the trip. With that said, I want my truck to have the same passing abilities as there are many occasions where it is needed. I can't imagine any rebuilt 307 letting me pass comfortably so I think a new 350/355/383 in going to be in order.

Now back onto the question. My truck has 3.08 rear gears, and a TH350 tranny. I debate on the "cheap" GM crate 350 with 250hp/350ft-lb's but just think it can't/won't breath enough to make passing quickly a reality. Do you folks think the Blueprint 355 w/310hp and 360ft/lbs would be enough or do I need to save a bit more and step it up to 375hp/400ft-lb 355? Or even blow that out of the water with a 383 pushing 400hp/450ft-lbs? I just don't know what to do at this point, and don't have enough seat time with this old ride to know what I need for power. Any ideas or thoughts from your experiences?

Thanks

[Kayotic]

That's a loaded question... lol...

May be good to ask in the performance section though.

[weircc]

dont sell yourself short on power

[capev86]

ummm.....13 seconds in the 1/4 is pretty good for a street car. only factory vehicles that will beat that are a corvette, viper or some exotic supercar.

it all depends on weight, transmission, tires, hp and tq, etc etc and a ton of other variables (as well as driver finesse) to get good performance numbers out of any vehicle. even the dodge ram with the viper package wouldn't break 13 seconds (0-60 in 5) due to weight, aerodynamics, balance, etc.

[b1kem1ke]

I have a 383 in my 67 and it has great passing power. My other car is a Speed 3 ( Modified to 300 hp ) The truck has as much passing power a different feel though.

Good luck with your project.

[capev86]

swap the 3.08 for a 3.73. it won't hurt gas mileage much and it will be night and day. the 3.08 is just plain lousy in a truck without a huge engine. it would be awesome with a diesel and work good in a stroker engine that doesn't pull big trailers.

[Ackattack]

I've had a couple of fast street cars (corvette and 3 LS1 firebirds) and now a G8 so I know what you mean.

Back in the day my 72 GMC had 3.08 gears and a TH350. I had a 327 in there that was putting out around 300HP and it had respectable passing power.

[Hottrucks]

Originally Posted by capev86

swap the 3.08 for a 3.73. it won't hurt gas mileage much and it will be night and day. the 3.08 is just plain lousy in a truck without a huge engine. it would be awesome with a diesel and work good in a stroker engine that doesn't pull big trailers.

I'll let you know how this goes I'm makeing a gear change but IMAO 3:73 is a great all around gear...my 308's such except on the highway..

Originally Posted by Ackattack

\Back in the day my 72 GMC had 3.08 gears and a TH350. I had a 327 in there that was putting out around 300HP and it had respectable passing power.

this is where opinions differ I have that set up and think it sucks...great if you want to go 75 in low and 100+ in second but not a good all around gear

now if you want decent power and want to have fresh power I would put in a vortec out of a truck with a carb ( bolt in stuff) that will be a big improvment then go for the gears....I'm doing gears and putting vortec heads on my 327 that should wake it up to be a good street pounder with decent mileage until I fine a caddy for real power

[68 short step]

you'll need atleast 600HP for a "good passing" experience

[Jacfourteen]

Originally Posted by 68 short step

you'll need atleast 600HP for a "good passing" experience

You know what they say, you can never have too much money or horsepower

[WyoGMC]

Originally Posted by capev86

ummm.....13 seconds in the 1/4 is pretty good for a street car. only factory vehicles that will beat that are a corvette, viper or some exotic supercar.

it all depends on weight, transmission, tires, hp and tq, etc etc and a ton of other variables (as well as driver finesse) to get good performance numbers out of any vehicle. even the dodge ram with the viper package wouldn't break 13 seconds (0-60 in 5) due to weight, aerodynamics, balance, etc.

As a former owner of a Ram SRT-10, all the car mags times are wrong. Those trucks can run under 12 seconds stock with a good driver(Regular Cab versions). The RC must have the driver mod to get a good time. My quad cab ran a best of 12.9 @ 109 with shorty equal length headers, CAI, custom PCM tune with drag radials.

To get back on subject a worked up 383 would do nicely.

[69 longhorn]

Originally Posted by Jacfourteen

You know what they say, you can never have too much money or horsepower

Or too much OLD whiskey, or too many YOUNG women Its not all about HP, but in my time I have found that GEARS show you a lot. For a mostly town driver, I would shoot for a 3.73 gear, dual purpose (a little hyway), I would go 3.42 on the gear....you still jump out good on a mid 3's gear, & dont rev too deep on the hyway. If you figure 300-325 @ the crank, you will have a "spunky" ride, that will get up & pass when you want it to. If the complete combo is "right on", you will see good things happen. crazyAL

[bigsnookmaster]

Just put a 150 shot to it, it will have plenty of passing power with the push of a button. Just kidding....but it would work!

[Beatcoaster]

Hehe, I had some good laughs there guys - good info. I have honestly thought about the 3.42 and think that it will probably be a good middle road to head down, but for now, am stuck to the 3.08 until it breaks from my new engine or I save up the cash for a 5-lug axle swap, new gears, and a posi/limited slip diff. From what I hear, I better suck it up and get the hot 355 or a 383. I will be going over a mountain pass hauling 2 dirt bikes, lots of gear/gas/tools and still having to pass people constantly as they can't seem to go the speed limit - at least 2 weekends a month - so power is a must have...I appreciate all the thoughts and comments guys!

[SCOTI]

How much HP do I need for easy passing at 60mph?

The more important need is TORQUE! Do the 383 w/a good flowing set of heads, a matched mild hydraulic cam, & a good dual plane intake to make optimum TQ @ cruising speed (est 2-2200rpm).

[petey-pablo]

I have a 454BB & Th400 with 3.73's in my 72short bed and I think I got some good passing power I even get sideways at times when I put my foot down I love my Kickdown but thats just me

[Smallz72project]

I agree with SCOTI. You are looking at the wrong variable in the equation. If speed is what you are after you build a motor with horsepower in mind. But Torque is what moves you when you need to be moved. With you having the 3.08s you are more high geared for running on the hwy and to equal out the get up and the go with that set up you need more push. With you driving plans I would recommend the 383. Its got the best of both worlds, just pay attention to you cam specs. You'll want an engine that stays fairly close if not in the power band at your cruising rpm. Say you are crusing at 2200-2400 and your engines peak torque hits at 2800-3000 rpm, you will be scooting pretty good once the go fast pedal is layed down. But as we all know HP/Tq go hand in hand. My vote is for the Stroker

[mosesburb]

I have about 230hp and 650+ft/lbs of torque. Even in a 6500lb vehicle, I have no issues whatsoever passing or pulling 7% grades over 75mph. I would shoot for something around those numbers--they work well for me.

Not much power, but a bunch of torque = fun vehicle to drive!!

[jim zag]

YOU NEED TORQUE not HP! My truck has a cheap 383 I built out of parts I had sitting around and the TORQUE it makes is unbelievable. I have 3.08 gears and 29 inch tires and I don't even NEED passing gear. I just did another one for my 68 C-20 that I will install in the springtime. I plan on using it to pull my car trailer. Just do a nice simple 383 and do not over build it. You will not be dissappointed! If you want my opinion on the details just PM me.

[LONGHAIR]

What everyone seems to be overlooking here is the transmission. Torque is exactly what you need, but you don't need excessive amounts all of the time, it just costs you in fuel milage. Torque multiplication comes from the gearing....transmission and rear differential.
Going to a lower gear (say 3.73) and then an over-drive transmission (say 700r4) that will bring the RPM back down for cruising will serve you best in all respects. It will allow for good passing power and still good mileage.

[SCOTI]

Originally Posted by LONGHAIR

What everyone seems to be overlooking here is the transmission. Torque is exactly what you need, but you don't need excessive amounts all of the time, it just costs you in fuel milage. Torque multiplication comes from the gearing....transmission and rear differential.
Going to a lower gear (say 3.73) and then an over-drive transmission (say 700r4) that will bring the RPM back down for cruising will serve you best in all respects. It will allow for good passing power and still good mileage.

I agree.... but even spending the money on new gears & OD trans won't make much difference because of this....

Originally Posted by Beatcoaster

I am looking at swapping in a new engine or rebuilding the tired 307 in my 69 long bed.

Bang for the buck is a combination of the motor & gearing. If the bank account dictates one or the other, I would remove the 'tired' 307 from the equation.

[Fitz]

Wrong question. How much can you afford?

You can never be too rich, too pretty or have too much horsepower.

This one passes everyone just fine. Uphill, downhill, or pulling a two ton trailer. Just doesn't matter!

[SCOTI]

Originally Posted by Fitz

This one passes everyone just fine. Uphill, downhill, or pulling a two ton trailer....

Everyone or everything except the gas station .

[PanelDeland]

I think you should build a plan.I would go with an OD tranny,a 383, and 3:42 gears.You may have to do one at a time to afford the upgrades.Modern GM drivetrains are usually set up as a 350,4L60E and 3:42's.The 4.3 engine gets the same driveline gearing(Standard).The GM engineers have done a lot of work to come up with a good combo for performance and economy,but the added torque of the 383 will feel really nice either under your right foot or your butt.(Seat of the pants)

[Beatcoaster]

The main problem is that it just sits in my driveway and collects mold. I have finished the interior and paint and just want the damn thing running and movable. I have a 2010 YZ450F that is sitting in my garage begging to be ridden, but doesn't have a truck to take it over the mountains ...

It is truly budget driven at this point and I want/need it up and running by late spring so I don't have much more time/money to save. I have about $4000 now that I can spend on the engine and tranny combo, and this is full turnkey, as everything currently is 40 year old scrap and I don't trust it one second on our 4 hour trips to our property. A new 450hp handling PA TH350 tranny with converter/fluid/dipstick is going to run me about $1000 so that leaves around $3000 for an engine. For about that, I could order the 310hp/360ft-lb Blueprint 355 from Jegs for $3200 with almost all the bolt ons and call it a day - but second guess that decision as I think it might not be enough. A 700R4/200R4 that can handle 400-450hp is going to blow my budget out of the water and leave me with nothing for an engine, as I would need to swap gears at the same time or just be lugging any engine I put in it - I would love to but my budget says "nope". Another thing I need to factor in is gas mileage, which changes this whole equation. It is about 250miles door to door, so a gas miser Edelbrock 1406 strapped to a 355 might be the best bet there, although my uncle gets 14-16 with his 383...so who knows...too many options to consider and ideas to weigh...