Rebuilding a 305 V6, worth it? Please come in!

[1LOW4X4]

Well looks like my search for my first truck, a 1964 GMC suburban, has all but ended with dead ends.

I do still have the motor, which spun a bearing. Its the original 305 V6.

I am on the hunt for that perfect (for me) original local 60's model truck, preferably a GMC stepside. When I get it, I would like to drop this motor in it.

My question. This motor is more of an industrial application I realize that. But it would do 70 all day long on the freeway.

Is it worth my time to rebuild this engine for a later truck. Money is no issue, and I dont want to build just another small block 350. I think that even if the motor that comes in my (future) 60's truck isnt a 305 v6, I'd still rather put that ear motor in it than a newer 350.

Thoughts? If this motor was rebuilt and fresh, would it last me a while, and would I be able to cruise around highway speeds without worrying about "over-taching" it?

I doubt I'd go with a 2 speed powerglide like it had behind it, prolly a 700r

[rwgregory]

In my opinion the GMC 305 V-6 is one of the best pure truck engines ever built. That means it does not like to rev, but it has unbelieveable bottom end grunt. Run tall back tires, tall rear end gears and an overdrive tranny and it will go freeway speeds all day long. There are ZERO hi performance parts made for it, but remember it was made for a truck, not a hot rod.

[padresag]

but there are a few things that you can do to sweeten them up. displacement in these engs go up to 478 cu in
ron

[tapeworm]

I'm sure you have checked out this site. If not, you must!

http://www.6066gmcguy.org/

If you simply want cheap, reliable, and easy go with a 350. If you break a part, you know the local auto parts store will have the part in stock.

If you want something a little different, with more character, not to mention torque, go with a GMC

[raycow]

I agree with all of the above. The V-6 should last you almost forever, and you won't be driving a carbon copy of everyone else's SB.

Ray

[slorio]

This thread is music to my ears, but then I have 305E in a 1966 GMC stepside. The key is overdrive transmission as others have mentioned above. With the low end torque of this motor, it is perfect for overdrive. I have a T85N behind mine with a 3.54 rear. Also, you better plan to upgrade brakes for what you want to do. 11" drum at 70 mph is a bit much.
regards,
Steve
New Orleans

[Clyde65]

I saw this here in the DFW CL...

http://dallas.craigslist.org/dal/cto/2047762002.html

And a 62 sub

http://dallas.craigslist.org/ftw/cto/2078001352.html

[jbgroby]

1Low,

I can speak from more experience than probably anyone on this BB on the worth of a V-6 I have restored 3 in my time, one from the oil pan up, (Katrina got that one) one from a used motor and one fully restored short black which I currently am using in my truck. There is ABSOLUTLY no finer feeling at a cruise night than having something different and RARE than the other trucks in on the field.

That feeling comes from not just being able to have something different, but having something HISTORICAL, I think less than 99% of the folks who drive their rides to cruise-ins and visitors have never even seen the VERY FIRST V-6 engine. Did you know that the engine made the cover of a the 1959 Popular Science?





This ones on eBay now $4.00 buy the copy

http://cgi.ebay.com/POPULAR-SCIENCE-...item563fedee00


There are so many things that were a FIRST with our engines and that paved the way for others, such as
First truck to have a DUAL master cylinder,
60 degree V, of course the 1st. V-6, (what SUV and Trucks have now)
High mounted Cam shaft (YOU CANNOT DRY SCUFF the cam, sits in a bath of oil at al times. (I wish they did this now, would not need special oil)
4 ringed pistons (3 compression and 1 oil ring)
The stock oil pump is capable of pumping out an incredible 14 GPM
The water pump can do 135 GPM

The engines were so over engineered that it was mind boggling to the regular truck driver and so reliable that you could only get a I-6 or V-6 from GMC unless you went out of your way to have a V-8 put in. then you lost all the torque.

There are things you can do your engine as I have done on mine to make it run easier, and lower the RPM.

1. Locate and install a 62-66 dual intake, then add a Holley 500 CFM carb, you need to make up a new accelerator linkage, but I have the master pattern and will make it for you at no cost.

See web shots link on the switch over here.

http://rides.webshots.com/album/560082574YsEssM

2. Figure out what rear end you have (a DANA 44 most probably) and change out the gears to a lower ratio, I went from 3.92 stock to 3.23 and dropped my RPM down 900 at least at 70 mph. I bought everything I need from Precision Gear.

See this album

http://rides.webshots.com/album/570438270cjSEvE

3. Change out the older distributor guts to a new Pertronix Electronic Ignition, $70.00 you can install yourself.

These are all the changes YOU WANT, you can add things like P/S to make life easier at tight turns. You need to find a V-6 P/S pump bracket though, rare but out here, and you put all modern pump and hoses on.

http://rides.webshots.com/album/571837084bSxNPf



My fully restored engine is here

http://good-times.webshots.com/album/568422172LCyGEI


I know it’s a long post, but I feel keeping the V-6 sets you apart from the heard, I like V-8’s - 350 and all the other toys you can shoehorn under a hood, but having something that is Unique, Different, and Historical far out weights the benefits of “modernizing” .

One of the things that many of the current car/SUV have gone to is a 60 degree V, they act as if it’s something new. Back 3 years ago, I decided to attend a car show at the Brian Harris Truck Dealership in Slidell, LA. (BIG GMC dealer) I register, set up my display, pop the hood and before you know it I got EVERY MECHANIC, Sales rep. and Mgr. out under the hood wondering where in hell I got the engine from. They absolutely had no idea that GMC made the first V-6. (that’s because many were not born yet) I decided to go to this show even before ANY of the upgrades and cleaning truck was nasty looking. The Mgr. of the dealer offered to buy my truck and when I said no we got to haggling back and forth and he even offered my a NEW crate engine to replace the V-6. He wanted (so he said) for the showroom. I agreed to let them display the truck in the showroom when finished for a month or so, (with a loner thrown, no less). You could probably do the same thing with your s

I cannot say enough about our engines, Please consider keeping it. IF not let me know and maybe we can work something out.

Jake Groby
Proud V-6 Owner.

[1LOW4X4]

Wow guys, thankd for all the info! I will be going over to get that engine later today and start the teardown.

jbgroby, Thanks for the links and the info. You've convinced me to rebuild this ol thing....

[jimmydean]

Only if you have the plaid valve covers.

[1adam12]

I have a 305 v6 in my 61 shortbed fleetside..The po gave me a box with the truck a brand new pretronix kit..He said u have to take dist out and put a bushing somwhere..I have done the holley 500 already....Does anybody have any suggestions..It looks like a simple install but the directions don't show anything bout a bushing...I m with you all keep the v6 there different..Also kinda cool..............

[markeb01]

The GMC V6 was probably the most over engineered automotive engine ever built. For uniqueness, torque, and longevity they’re in a class of their own. The real answer lies in what you really want. One of my sons built a 401 Buick. It’s a sweet engine, but cost him over $3,000 after a lot of searching for some common but hard to find parts. Certainly a 350 Chevy would have been easier and less expensive, but no matter if it’s an Oldsmobile, Chrysler hemi, or GMC V6 – if it’s what you love it’s worth the cost and effort to have something different.

I analyzed this decision myself about 20 years and went the other direction, replacing the V6 with a 350. My engine had cracked valves but continued to run reasonably well. I checked with several reputable shops I trusted, and several told me they weren’t interested in rebuilding it at all. Two that were willing wanted over $2500 for the effort. At the time a brand new 350 was just over $1,000. Since I wanted a high performance long distance hot rod commuter, the decision was rather easy. Personally I’ve never regretted the decision, but I also enjoy studying a restored truck with one of these monsters installed.

If you decide to keep the V6, do yourself a favor and join the Jolly GMC site if you haven’t already. They have the corner on V6 expertise and can no doubt help with advice and parts.

[1LOW4X4]

Originally Posted by markeb01

The GMC V6 was probably the most over engineered automotive engine ever built. For uniqueness, torque, and longevity they’re in a class of their own. The real answer lies in what you really want. One of my sons built a 401 Buick. It’s a sweet engine, but cost him over $3,000 after a lot of searching for some common but hard to find parts. Certainly a 350 Chevy would have been easier and less expensive, but no matter if it’s an Oldsmobile, Chrysler hemi, or GMC V6 – if it’s what you love it’s worth the cost and effort to have something different.

I analyzed this decision myself about 20 years and went the other direction, replacing the V6 with a 350. My engine had cracked valves but continued to run reasonably well. I checked with several reputable shops I trusted, and several told me they weren’t interested in rebuilding it at all. Two that were willing wanted over $2500 for the effort. At the time a brand new 350 was just over $1,000. Since I wanted a high performance long distance hot rod commuter, the decision was rather easy. Personally I’ve never regretted the decision, but I also enjoy studying a restored truck with one of these monsters installed.

If you decide to keep the V6, do yourself a favor and join the Jolly GMC site if you haven’t already. They have the corner on V6 expertise and can no doubt help with advice and parts.

Thanks fella! Will do!

[jbgroby]

Originally Posted by 1adam12

I have a 305 v6 in my 61 shortbed fleetside..The po gave me a box with the truck a brand new pretronix kit..He said u have to take dist out and put a bushing somwhere..I have done the holley 500 already....Does anybody have any suggestions..It looks like a simple install but the directions don't show anything bout a bushing...I m with you all keep the v6 there different..Also kinda cool..............

I Adam see pics All you do is removethe condenser and screw the modual in place and connect the red and black wire. The I di not remove any bushing, he may be confused with CHANGING out the entire dist to a BUICK V-6 that is SET UP for elec. ign. Although I'm pointing to different things in the pics, you can see the black box (21AA-V4) on the dist. that is the petr unit, next phot shows the two wires red.blk. that connact to the top of the coil.

[1LOW4X4]

Heres the link to my 305 V6 build thread, hope all you guys come in and give me some pointers.


http://67-72chevytrucks.com/vboard/s...d.php?t=433505

[factorystock]

These engines were designed for high torque at low rpm for longeviety. Here are some testimonials from back in the day.

[1LOW4X4]

Very cool!

[factorystock]

Another happy owner!

[Shaky]

I like that pic of the '64 Suburban - looks like the tongue is hanging out.

[T Herder]

If you decide to rebuild the V6, here would be some of my recommendations.

I’ve run these trucks for forty years with every enhancement known, I have three of them. The best performing 305E V6 is in the 65 4x4. Log book shows best mileage, 18.6, worst 6.7, but that was pulling 21% grades with a 12,500 trailer in four wheel low.

Some of the modifications:
Mallory Mag-Lite distributor, they’ll make you one, the only part you need is the drive gear, haven’t touched mine in fifteen years. Have it made with computer controlled timing.

TBI fuel injection, it never fails to start on first crank, runs great from sea level to +10,000 feet.

Five pass radiator, gauge never moves, be it –10F or +110F pulling the steep grades with the trailer.

Have the rear cam bearing race machined to provide continuous upper drive train oiling, works better than the stock pulse oiling, especially working it hard.

Have custom sodium filled valves made along with hardened valve seats installed, some factory motors came this way, this is to accommodate unleaded fuel since lead was banned.

Use four ring pistons, they can be found, at oil change time the oil looks new, still hard to see on the dipstick.

Dismantle and thoroughly clean the crankcase ventilation valves that are in the heads, haven’t had to replace any yet on three trucks in forty years.

Remove the pressed in crankcase ventilation breather and pipe a new line to a K&N air filter, smog laws.

These motors are internally balanced, so balance EVERYTHING, crank, rods, pistons, plus the externals ie: crank pulley, flywheel, clutch etc.

Check the oil pump clearances, mine is stock, just cleaned it up, runs 50 lbs, the clearances ARE critical.

I run a Gear Vendors overdrive married to an SM420 with a divorced NP205 transfer case, original 4.56 gears, BFG 35x12.50x16.5 AT’s. I’m changing to 33 inch tires to raise the RPMs to the sweet spot when traveling most of the time at 20,000 GCVW.

If you go to fuel injection and stay with the stock tank you’ll need a fuel return line. Buy a new stock replacement fuel pickup and sending unit. Carefully remove the sending unit. Sand an area of approximately one inch diameter to bare metal on both sides of the new units mounting plate. Drill a 3/16” hole in the mounting plate and removed any burrs. Support the mounting plate on the internal side of the plate with a 9/16” six sided socket, the six sides towards the mounting plate. Take a 5/16” diameter tapered drift punch and drive it through the hole to form a tapered flare recess. This recess will be on the outside of the plate. Using a tubing bender, bend a 5/16” steel tube to parallel the fuel pickup line ending at the same bottom level BUT returning to the OPPOSITE side of the tank. Bend the external side of the return tube down to parallel the feed line. Carefully work the new return line through the 5/16” hole to what you THINK might be its final position. Then try fit it into the tank to confirm it will install with no problems. Once this is accomplished, Silver solder the 5/16” tube into the mount plate using 45% Silver solder.
If you’re hesitant to try this, practice first with a piece of scrap sheet metal and scrap tubing of the same gauge as your new replacement mounting plate.

There are more mods available, you did say money was no object.
Best regards,
THerder

[Corts60]

Originally Posted by T Herder

If you decide to rebuild the V6, here would be some of my recommendations.

TBI fuel injection, it never fails to start on first crank, runs great from sea level to +10,000 feet.

ITHerder

Do you have any pictures of this set-up? I would be very interested to see the TBI on a V-6.

[markeb01]

Originally Posted by T Herder

If you decide to rebuild the V6, here would be some of my recommendations.

THerder

Excellent and nicely detailed information. Thanks for sharing.

[68GMCCustom]

If you want something different...and the closest gas performing motor to pull like a diesel...redo the V6 with your choice of trans and run a low gear with a overdrive (x2 if possible) for the highways.

[T Herder]

Pic of the TBI.

[duallyjams]

Originally Posted by T Herder

Pic of the TBI.

who,what,where,when and how, we need much info on this set up.