305 to 350, what can i bring over? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ocbaud · 12-11-2003, 04:08 PM

will the harmonic balancer work?

also,i know i'll need a new flywheel, but will any th350 flywheel work with an 85' -below block and a th350c?

**swervin ervin** · 12-11-2003, 04:19 PM

Yes, your balancer will work, but you will need to use the 305 timing cover since the pointer is at 12:00. As long as the flexplate is from a 85 down engine, it will work. 86 up went to the one piece seal and was different bolt pattern.

Everything from the 305 will bolt on. But forget the heads, even though they will bolt on, the valves are too small and the chambers too small. Besides, a 305 head is the worst designed head GM ever made.

86SILVERADO · 12-11-2003, 05:10 PM

I would think that the 350 would need the bigger balancer to counteract the greater vibration from the larger rotating assembly.

**swervin ervin** · 12-11-2003, 05:29 PM

Personally, yes, I prefer an 8" balancer on 350's. But, it has nothing to do with vibration. If your engine vibrates, a balancer, or as the proper term goes, harmonic dampener, will not stop it. All the dampener does is like it says, dampen harmonics. It really doesn't matter what size, as long as it is used to balance the assembly.

I seriously doubt the assembly will be truely balanced anyway. Not for 700 bucks. A true balancing job is where they weigh each component to find the lightest one, and then remove weight off of the others to make them weigh the same. Every piston and rod needs to be weighed and matched. This is the only way to balance an internally balanced engine.

*1FaastC10* · 12-11-2003, 08:06 PM

why not spend the extra money on a new high quality balancer as protection on your brand new rotating assembly?

ocbaud · 12-11-2003, 08:09 PM

Quote:

Originally posted by 1FaastC10
why not spend the extra money on a new high quality balancer as protection on your brand new rotating assembly?

i planned on it. just wonder really mostly about what kinda flywheel i need to get

phantom dually · 12-11-2003, 08:40 PM

Flywheel can be had CHEAP. Hell you can get a SFI unit for $50.

86SILVERADO · 12-11-2003, 09:38 PM

I had to buy a new flexplate for the exact reason that swervin mentioned and it was only like 25 bucks.

lukecp · 12-11-2003, 09:47 PM

I bought a flexplate for my truck for like $25 a few years ago.

I would strongly reccomend replacing it...it is so cheap and easy to put on while the motor is out, and will give you hell to replace it if your ring gear gets a bit worn in the future.

ElGracho · 12-11-2003, 11:13 PM

Eric knows all about the woes of a broken flex plate...

86SILVERADO · 12-11-2003, 11:46 PM

Quote:

Originally posted by yellow72custom
I bought a flexplate for my truck for like $25 a few years ago.

I would strongly reccomend replacing it...it is so cheap and easy to put on while the motor is out, and will give you hell to replace it if your ring gear gets a bit worn in the future.

I go through enough trannies towing my tractor around all year that it shouldn't be too much trouble to replace it when it does go.

MylilBowTie · 12-12-2003, 12:43 AM

What kinda transmission you got??

ocbaud · 12-12-2003, 01:22 AM

Quote:

Originally posted by MylilBowTie
What kinda transmission you got??

th350c

86SILVERADO · 12-12-2003, 01:26 AM

Well so far I have killed one 700 and one 350 in four years. This is in a 1/2 ton truck puling an 18' trailer and john deere 855 about 4500 lbs total and I do have a remote cooler for the tranny. I'll just go to the boneyard and get another for 100 and throw it in and it should last me another couple years. Thats why I bought the 67. Now I have a sm420 and 4.10 in the rear.

12-11-2003, 04:08 PM	#1
ocbaud Garage Queen Material Join Date: Oct 2002 Location: USA Posts: 4,129	305 to 350, what can i bring over? will the harmonic balancer work? also,i know i'll need a new flywheel, but will any th350 flywheel work with an 85' -below block and a th350c?

12-11-2003, 04:19 PM	#2
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	Yes, your balancer will work, but you will need to use the 305 timing cover since the pointer is at 12:00. As long as the flexplate is from a 85 down engine, it will work. 86 up went to the one piece seal and was different bolt pattern. Everything from the 305 will bolt on. But forget the heads, even though they will bolt on, the valves are too small and the chambers too small. Besides, a 305 head is the worst designed head GM ever made. __________________ Mike 1985 Chevy C-10

12-11-2003, 05:10 PM	#3
86SILVERADO Registered User Join Date: Dec 2002 Location: Hills of Western Mass Posts: 626	I would think that the 350 would need the bigger balancer to counteract the greater vibration from the larger rotating assembly. __________________ 86 Silverado C10 back to 305 power! 67 C30 Dually Dump, with 350 transplant, Rockhauler 05 Duramax 3500 "If at first you don't succeed, try a bigger hammer" Member of the 1-Ton club!

12-11-2003, 05:29 PM	#4
swervin ervin You get what you pay for Join Date: Dec 1999 Location: Cherryville, NC Posts: 4,798	Personally, yes, I prefer an 8" balancer on 350's. But, it has nothing to do with vibration. If your engine vibrates, a balancer, or as the proper term goes, harmonic dampener, will not stop it. All the dampener does is like it says, dampen harmonics. It really doesn't matter what size, as long as it is used to balance the assembly. I seriously doubt the assembly will be truely balanced anyway. Not for 700 bucks. A true balancing job is where they weigh each component to find the lightest one, and then remove weight off of the others to make them weigh the same. Every piston and rod needs to be weighed and matched. This is the only way to balance an internally balanced engine. Last edited by swervin ervin; 12-11-2003 at 05:36 PM.

12-11-2003, 08:40 PM	#7
phantom dually Project92 SWB stepside Join Date: Feb 2003 Location: Louisville KY Posts: 4,792	Flywheel can be had CHEAP. Hell you can get a SFI unit for $50. __________________ 92 C1500 stepside 496 Stroker Competiton Engineering Ladder bars/QA1 coilovers. Dana 60 rear with 4.10 gear and posi. Bonspeed Palisade 20x12 in rear w/335/30/20 and 20x8.5 front w/245/40/20. 5/8 drop with Belltech springs/DJM spindles/drop shocks. WWS Progress thread http://67-72chevytrucks.com/vboard/s...d.php?t=140448

12-11-2003, 08:06 PM	#5
1FaastC10 Account Suspended Join Date: Oct 2002 Location: Elkhart, IN Posts: 6,399	why not spend the extra money on a new high quality balancer as protection on your brand new rotating assembly?

12-11-2003, 09:38 PM	#8
86SILVERADO Registered User Join Date: Dec 2002 Location: Hills of Western Mass Posts: 626	I had to buy a new flexplate for the exact reason that swervin mentioned and it was only like 25 bucks. __________________ 86 Silverado C10 back to 305 power! 67 C30 Dually Dump, with 350 transplant, Rockhauler 05 Duramax 3500 "If at first you don't succeed, try a bigger hammer" Member of the 1-Ton club!

12-11-2003, 09:47 PM	#9
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	I bought a flexplate for my truck for like $25 a few years ago. I would strongly reccomend replacing it...it is so cheap and easy to put on while the motor is out, and will give you hell to replace it if your ring gear gets a bit worn in the future. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

12-11-2003, 11:13 PM	#10
ElGracho Gentleman Jim Driver Join Date: Nov 2002 Location: Poulsbo, WA Posts: 1,553	Eric knows all about the woes of a broken flex plate... __________________ Joe '75 GMC Gentleman Jim '84 Chev C10 Short Wide - Super duper plain (manual steering, manual brakes, no dome light, no cig lighter) '85 Chev C10 Short Wide - Super plain Vortec 4.8 4L60E trans also: '81 K30, '83 C30 Crew Dually, '84 M1028 CUCV, '85 M1009 CUCV, another '85 C10 SWB, '89 R3500 Flatbed

12-12-2003, 12:43 AM	#12
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	What kinda transmission you got?? __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

12-12-2003, 01:26 AM	#14
86SILVERADO Registered User Join Date: Dec 2002 Location: Hills of Western Mass Posts: 626	Well so far I have killed one 700 and one 350 in four years. This is in a 1/2 ton truck puling an 18' trailer and john deere 855 about 4500 lbs total and I do have a remote cooler for the tranny. I'll just go to the boneyard and get another for 100 and throw it in and it should last me another couple years. Thats why I bought the 67. Now I have a sm420 and 4.10 in the rear. __________________ 86 Silverado C10 back to 305 power! 67 C30 Dually Dump, with 350 transplant, Rockhauler 05 Duramax 3500 "If at first you don't succeed, try a bigger hammer" Member of the 1-Ton club!



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