Author Topic: Rebuild the original 305 or built a 350?  (Read 3719 times)

Offline 1976Scottsdale

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Rebuild the original 305 or built a 350?
« on: December 15, 2005, 09:25:00 PM »
Okay, I have the original 305 engine from a 1985 K-5 blazer that I am trying to get.  The engine is already mine.  I have owned and rebuilt 3 350's and a 327.  I have never done a 305 before.  I have heard that they are junk, but I do not tend to agree.  They seem to do just fine in two trucks that I know of.  Just looking for some advice here.  I am kind of a fan of keeping these old trucks all original as much as possible.  If I get the Blazer, it will be a driver and an occasional play toy.  Will I really notice a difference in power between a well put together 305 and a well put together 350?  Would also like some advice on pistons, cams, rings and what not.
Rebuild and improve original 305.
Build a 350 for it.

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Offline cardinalredC10

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Re: Rebuild the original 305 or built a 350?
« Reply #1 on: December 16, 2005, 01:10:00 PM »
My buddy had a 305 in his 84 Blazer. He rebuilt it with perfomance parts but kept in mind that you can't really put a big cam or large diameter headers and what not. As long as you put parts on it that were designed for the 305 you will be surprized. He had a cam, intake, good carb, small tube headers and ignition (pretty sure that was about it) and he could spin his 33's all day long, not to mention that it wound up pretty quick.  


Offline Lt.Del

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Re: Rebuild the original 305 or built a 350?
« Reply #2 on: December 17, 2005, 08:15:00 PM »
If you rebuild a 350, make it a 383 stroker.  It'll give you plenty of torque w/ no more cost of a 350 rebuild, just throw in some parts from a 400 (crank, balancer, flexplate)  w/ some 350 rods that were milled for the 383 conversion.  

SgtDel
79 Big 10 383 stroker

Edited by: SgtDel at: 12/20/05 10:39 am

Offline jo3y1nf4nt3

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Re: Rebuild the original 305 or built a 350?
« Reply #3 on: December 19, 2005, 08:31:00 PM »
im in the same predicament.  if anyone remembers, i had a main cap bolt snap on me so i took it to the mach. shop and they removed it for me.  anyways, it was just gonna be a 'stab the motor back in the truck and use it as is' deal, but i wound up buying new bearings, cam, gasket kit, timing chain, pushrods, lifters, maybe some 1.6:1 roller tipped rockers, gonna hone the bores, new oil pump, new paint on the motor....so i guess i'm just going to keep this motor until it falls apart (hopefully some 150,000 miles away)  all in all, i have listed above, plus purchased prior to this month (as in years ago) performer RPM intake, hooker headers, 1406 600cfm edelbrock, and homemade forced air induction.  hopefully it'll be stout and with a trade to a 3.73 gears, it'll liven it up some more.  i wish you luck as i have my fingers crossed that my engine will pan out and provide me uneventful transportation.  anyone have any ideas?  (besides ditch the 305 for a 350!!!)  later, joey.  


jo3y in baytizzle (baytown y'all!)
"if only i could soothe my hunger by rubbing my belly" - diogenes

Offline H A REDNECK

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Re: Rebuild the original 305 or built a 350?
« Reply #4 on: December 22, 2005, 10:13:00 AM »
GO WITH THE 350. YOU WILL BE GLAD YOU DID. MY 305 HAD 176,000 ON IT AND STILL RAN FINE, SOLD IT FOR $500.00. IT WAS A GOOD MOTOR FOR DRIVING AROUND BUT THATS ABOUT ALL. GAS MILAGE ABOUT 15MPG. TOWING SOMETHING WAS DIFFICULT AND POWER WAS NOT THERE. I BUILT A 400SBC. IT HAS PLENTY OF POWER AND MPG WHEN I KEEP MY FOOT OUT OF IT. IF YOU GO WITH THE 350 AND BUILD IT MILD THE MPG,S WILL BE ABOUT THE SAME AS THE 305. YOU CAN GET 300HP FROM THE 350 EASY. IF YOU ARE GOING TO TOW SOMETHING BE CONSERTIVE ON CAM SELICTION. IF YOU WANT A LOPE IN YOUR IDLE USE THE COMP CAM PART # 12-238-2 XE262H-10.


Offline adamrx7

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Re: Rebuild the original 305 or built a 350?
« Reply #5 on: January 01, 2006, 11:01:00 PM »
I am building a 305 for my 73' GMC right now. The truck had a 350 in it from the factory, but by the time I got it it had a 305 (who knows what happened to the 350). I feel the 305 will last longer then a 350, wich one would you trust crossing the desert? The 305 is a much thicker casting and wont overheat as easly. I work at Allied Motors(www.strokerkits.com) so I have full access to the most advance machine equipment. I first hot tanked the block and checked it for cracks and measured the line bore, all where perfect (think casting) next I put it in the shot-peen machine to clean it real well. After that I put it on the RMC CNC machine to be decked,blue printed and bored. Heres a pic of it finished on the CNC machine. (phone camera) img.photobucket.com/album...3300_1.jpg  www.strokerkits.com/100_0379.jpg
the block blueprinted at .040 over it would of cleaned at .030 over but not be blueprinted. That extra .010 doesnt matter with the thick casting. I also balanced the rotating assembly, the pistons all weight the same with NO difference so are the rods down to a tenth of a gram. The crank with the flywheel and balancer on plus the bob weights started out 55 grams off on the flywheel side and 53 grams off on the balance side. When I was finished they where under 0.10 grams combined! This motor should last a LONG time and spin up quickly. I decked the block to deck height of 9.002 to add some compression.
The head swhere totaly gone through also, I installed new valve guides with valve job on the Sunnen valve/guide machine after that I milled .015 off each to ferther bump the compression. I went with a Claimer flattop piston also. I went with a "stage 2" tow/milage cam. Other then that I had the carberator rebuilt at Bradley carborators, they do awsome work and are very close to me. Its comming togeather well.  

Adam
93 RX-7 and
89 Colt(4g63)

Edited by: adamrx7 at: 1/1/06 11:03 pm

Offline adamrx7

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Re: Rebuild the original 305 or built a 350?
« Reply #6 on: April 03, 2006, 09:59:00 AM »
Truck is running great I havent regretted the 305 yet. I am thinking about building a 383 for it thoe. Heck I only got $600 in this motor.

Adam
93 RX-7 and
89 Colt(4g63)