im wanting to go from a 305 to a 327 im trying to figure out what i need to do as far as a new transmission ive looked through the forums and havnt found anything that helps any one have anything that might help plz post but only postive things

 

you want a real old world 327 or a new one?
you can destroke a 350 to a 327 - they both had 4 inch bores. so does the 302 too, and the 283 - although im not sure about the 283 anymore.

you do understand that you lose low end torque in exchange for higher rpm's.

lots of people love the tone of a 327 - just different than a 350.

and the 302 was definitely a high rpm motor but not much low end torque.

you should read up on the stats and opinions of each.

keep us advised.

 

Any transmission that will bolt to a 305 will bolt to a 327.
A 283 doesn't have a 4" bore. It has a 3.875" bore and a 3" stroke.
Possibly helpful link: https://www.thirdgen.org/forums/engi...t-fiction.html

 

Unless you need a smaller engine for a specific class of racing etc, the cost of a new engine is the same and a 350 is a lot more common to use. You can't take the 305 and make it into a 327 if that's what you're planning on doing.

Externally, all the SBC engines are the same size. The only difference you might encounter is if the engine has a one or two piece rear main seal. That will determine which flexplate needs to be used but your transmission will bolt up to all the SBC and BBC blocks.

Finding and trying to use an older engine runs into other problems. The first being the heads. At the time, the old performance heads were the best things to use. Now there are so many aftermarket choices available, it's not worth the time and money to use old heads. Older heads may not have accessory bolt holes which makes installing alternator, power steering pump etc difficult.

 

I agree, a 350 or 383 would be a better choice. I am building a 327 currently because I got a forged crank, rods with ARP bolts, machined block, ported double hump heads with screw in rocker studs, aftermarket valves and springs, and machined spring seats, all for free. I also know that any of the parts that I am buying can be used on most SBC's, if I decide I want a larger displacement engine later.

To solve the accessory mounting problems, I am converting to manual steering and buying an aftermarket alternator bracket.

 

thanks greg - been a long time since i played with a 283. now that i think about it we used to bore them out to 302 and stroke to 318 - or was it 317.
but thanks for pointing that out.
and i know that the blocks are different from old world ones and current ones. the old ones you could bore and bore the new ones are lighter because they have water jackets everywhere.

 

thing is we already have a 327 and im not even able to drive yet (legally) so im worried bout over powering but i just want to keep my options open in case something happens to the current 305 i just wanted to try to figure out how much/ were i could get a new transmission if something were to happen to the current one

ps thank yall for all the info its amazingly helpful

 

Another thought, just an FYI - IF you have a large journal 327, then adding a 350 crank, rods, and pistons essentially makes it a 350.

 

Are you running a carb TBI or TPI? I had an old 11:1 327 running TPI. It ran awesome.

What year is your car? You are going to have to find out if your 305 is a two peice or one peice rear main seal.

I ran the serpentine accessories that came with my original 305 engine on my 327. You will have to make sure the accessory holes in the brackets line up with the ones on the heads too.

When the heads 92 camaro's 305 cracked I replaced it with that 327. I reused the TBI intake and throttle body, got a chip, swapped in 350 TBI injectors, and put an msd 6A box and Blaster II coil. I later acquired a speed density TPI setup, got another chip and ran that for a couple years.

I think I did have to dig up a two peice rear main seal flexplate for it.

If I remember correctly the one peice rear main seal and roller camshafts were introduced in 1988. But you should check to be sure.