350 rods in a 305... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Chevelle454 · 05-28-2004, 12:08 PM

Can 350 rods be used in a 305? I am going to rebuild my '84 305 and I know that 305's have relatively weak bottom ends. Could I use the 350 crank and rods from a 1987 350 TPI(out of a camaro)? Are the rods the same size and the crank the same size? Will it all just bolt right in with the standard bearings?

Thanks...

Warrens69GMC · 05-28-2004, 12:28 PM

Yes it will all bolt in and work, but you will need to have it balanced. The 305 has a weak bottom end due to only being a 2 bolt block.You can convert the 305 to a 4bolt with the 350 caps and align hone. Or, even better, splayed caps make it MUCH beefier. Use ARP bolts on the rods & mains and it is as stong if not more, than a stock 350.
warrens69gmc

motoretro · 05-28-2004, 12:37 PM

The 305 crank carries same casting number as a 350 although it is balanced differently to accomodate the lighter pistons on a 305. The 350 rods are same length and journal sizes are the same and should not be a problem. If you install the 350 parts, you will have to have quite a bit of material removed from crank to balance out with 305 pistons. When you pull your pan, look at the notch cut into the 305 crank's throws. You should be able to lay a straight edge in this notch from front to rear. Thats the amount of material that has to be removed. Bearing sizes are same. 350 crank drops in...I personally feel the bottom end is fine with whatever hp mods you may make to the 305
Good luck
motoretro

*1972C10* · 05-29-2004, 02:36 AM

That 2 bolt 4 bolt stuff is retarded .

The way they are balanced the crank that is.. is by the holes being drilled depper in 305s Ive ran 305 crank rods in 350s before and not getting balanced without probs but never the other way ..

I tore down a 305 out of a boat awhile back It had "X" rods there currently in my 3/4 ton

Depending on what year 305 you have the later model ones had "X" rods Or so my engine builder says I tore down a 305 out of an 86 gmc the other day it had x rods but two were trashed due to cam breaking ,

And if you were to get 350 4 bolt caps and get them aling bored on a 305 that would be the lamest thing i have ever heard you could get a 350 40 bolt core for what that would cost.

And if you decide to put some ARP bolts in it I have a set friend bought a few years ago he ended up getting a windage tray And it required studs Thus never used them so i wound up with them .

05-28-2004, 12:08 PM	#1
Chevelle454 Registered User Join Date: Aug 2003 Location: MN Posts: 380	350 rods in a 305... Can 350 rods be used in a 305? I am going to rebuild my '84 305 and I know that 305's have relatively weak bottom ends. Could I use the 350 crank and rods from a 1987 350 TPI(out of a camaro)? Are the rods the same size and the crank the same size? Will it all just bolt right in with the standard bearings? Thanks... __________________ 1972 C10 1972 C20

05-28-2004, 12:28 PM	#2
Warrens69GMC Registered User Join Date: Jan 2003 Location: Safford,AZ Posts: 3,612	info Yes it will all bolt in and work, but you will need to have it balanced. The 305 has a weak bottom end due to only being a 2 bolt block.You can convert the 305 to a 4bolt with the 350 caps and align hone. Or, even better, splayed caps make it MUCH beefier. Use ARP bolts on the rods & mains and it is as stong if not more, than a stock 350. warrens69gmc

05-28-2004, 12:37 PM	#3
motoretro Registered User Join Date: Jul 2003 Location: Mid-MI Posts: 110	The 305 crank carries same casting number as a 350 although it is balanced differently to accomodate the lighter pistons on a 305. The 350 rods are same length and journal sizes are the same and should not be a problem. If you install the 350 parts, you will have to have quite a bit of material removed from crank to balance out with 305 pistons. When you pull your pan, look at the notch cut into the 305 crank's throws. You should be able to lay a straight edge in this notch from front to rear. Thats the amount of material that has to be removed. Bearing sizes are same. 350 crank drops in...I personally feel the bottom end is fine with whatever hp mods you may make to the 305 Good luck motoretro __________________ motoretro 1972 Chevrolet Custom 10 Lwb www.esivart.com/ebay/truck.gif

05-29-2004, 02:36 AM	#4
1972C10 Account Suspended Join Date: Dec 2003 Location: Texas Posts: 2,686	That 2 bolt 4 bolt stuff is retarded . The way they are balanced the crank that is.. is by the holes being drilled depper in 305s Ive ran 305 crank rods in 350s before and not getting balanced without probs but never the other way .. I tore down a 305 out of a boat awhile back It had "X" rods there currently in my 3/4 ton Depending on what year 305 you have the later model ones had "X" rods Or so my engine builder says I tore down a 305 out of an 86 gmc the other day it had x rods but two were trashed due to cam breaking , And if you were to get 350 4 bolt caps and get them aling bored on a 305 that would be the lamest thing i have ever heard you could get a 350 40 bolt core for what that would cost. And if you decide to put some ARP bolts in it I have a set friend bought a few years ago he ended up getting a windage tray And it required studs Thus never used them so i wound up with them .



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