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Author Topic:   305 & 350 motors
Rookieracer76
Dirt Freak

Total posts: 289
posted November 27, 2002 12:13 PM  
What are the main differences between 305 sbc and 350 sbc ? are the heads the same ? whats different ?? Thanks to anyone with help !

66jj
Dirt Forum Champ
Total posts: 823
posted November 27, 2002 12:53 PM  
SAME CRANK 305-350
BORE ON A 350 4"
BORE ON A 305 3.875"

HEADS ON 305 ARE LIGHTWEIGHT CASTINGS, SMALLER VALVES AND RUNNERS AND COMBUSITON CHAMBERS.


Rookieracer76
Dirt Freak

Total posts: 289
posted November 27, 2002 01:11 PM  
i'm not good when it comes to engines. So would it make sense to put 305 heads on a 350 ? i was also thinking of building a stroker so would the 305 heads work well ? Thanks !

uforacing51
Dirt Forum Champ
Total posts: 570
posted November 27, 2002 01:48 PM  
In some cases, (not all)the 305's have a head with a smaller chamber, which gives you a higher compression ratio. (compression good!!) The best thing to do is purchase a book on head castings. I think Steve Smith auto sports has a book that fits the bill. to answer your question, yes, you can use the 305 heads on a 350, they bolt right up. Just make sure you have the valve size you want, and the heads breath good.

[This message has been edited by uforacing51 (edited November 27, 2002).]

loojack
Dirt Maniac

Total posts: 196
posted November 27, 2002 03:05 PM  
Alot of guys run 305 heads on 350s with alot of success. I've been told the best casting is the 416 I think the whole # is 14014416. Other # are 601, and 434. Most 305 heads have small chambers 58 to 60 cc's. Hope this helps. loojack

Rookieracer76
Dirt Freak

Total posts: 289
posted November 27, 2002 03:22 PM  
thanks to all you guys that are helping ! theres only one thing. loojack you listed of couple of casting numbers to look for. The only thing i looked at the casting numbers in the toolbox and couldnt find any that match. can someone help me out ? Thanks!

jhon hollomon
Dirt Freak

Total posts: 468
posted November 27, 2002 03:46 PM  
The 14014416 was made after 1980 and has 1.84/1.5 valves with a 59 cc combustion chamber.The 14022601 heads were used from 79 to 86. They have the same valvesize as the other heads but the combustion chamber is 52.3 cc's.The 354434 casting heads are 1.84/1.5 valve heads. They have a 60 cc combustion chamber.Hope this helps.

6pack
Dirt Maniac

Total posts: 171
posted November 27, 2002 05:16 PM  
Bore on a 305 is 3.736. The 3.875 bore was used on 283's and 307's. Using the 305 heads on a 350 is a "cheaper" way to get compression up, but you lose "flow" compared to the older "double hump"(461,462,291,186,etc.)heads.

rusty9cab
Dirt Full Roller

Total posts: 38
posted November 30, 2002 04:29 PM  
76. if you have to run 305 heads look for some off of a monte carlo ss or camaro.. something that had the 305ho motor. I raced some for 2 races and then switched to some double hump. The power difference was worth the loss of compresion, and you can shave the 350 heads and get a 58cc chamber. Go with the 350 heads would be my advice.

Rookieracer76
Dirt Freak

Total posts: 289
posted November 30, 2002 05:22 PM  
I have a 305ho motor in my monte now. So i guess i'll check those numbers out and use those. thanks for all the help !

30rulz
Dirt Forum Racer

Total posts: 87
posted December 31, 2002 05:57 PM  
do you need to do any machine work on the 305 heads to run them on a 350?

Eljojo
Dirt Forum Champ
Total posts: 968
posted January 01, 2003 08:15 AM  
30 rulz, No, machine work is not required-it's a bolt-on. But, as stated in previous posts, look for the SS heads which have the 1.94 valves. They still aren't "first pick" of the SBC heads out there, but like the Duke said, "A man's gotta do what a man's gotta do!"

restore1
Dirt Roller

Total posts: 10
posted January 02, 2003 08:51 PM  
I have the 14022601 heads. What could be done to beef them up? Thanks.
Restore1

PEDDLER
Dirt Freak

Total posts: 446
posted January 04, 2003 09:02 PM  
Casting numbers are available on www.mortec.com

Good luck
Jim

rickb33
Dirt Forum Racer

Total posts: 99
posted January 07, 2003 08:49 AM  
rebuilt 305 h.o. motor.has less than an hour on engine.runs very good.$500 as is.has 4 barrel manifold.x-rods.

o5racer
Dirt Freak

Total posts: 402
posted January 18, 2003 09:01 PM  
492 cammelback + .090 angle mill = 55 cc chambers.

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