The Stovebolt Site Forums The Shop Area The HiPo Shop 350 to 383

i have an 1973 350 motor i would like to have rebuilt i dont have much motor knowledge but im thinking of making it a 383 dont know what im getting into so im looking for some feedback also want to add a 700r transmisson any feedback would be much appreciated

350 to 383 is done with a 400 crank or aftermarket crank (not costly)..find a good machine shop and have work done or find friend with exp...doc

If you have an engine stand and a good rebuilding manual you can do the work yourself. It will give you a great sense of accomplishment and you can tell people you built your own engine. It is not really very difficult unless you have zero mechanical appitude but then if you did not have the ability/interest you would probably not be here asking questions.
Find a friend who can help you if you get stuck on anything.
Good luck and have fun.

Houston is right-me & a buddy built a 383 wayyy back in the mid 80s when I was a teenager-I read about them in Hot Rod mag. The machinist who cut the crank would not warranty it, felt it wasn't gonna work. We built it on a table in a 9x12 shed. They are now the most popular circle track engines around here now. You need 400 rods & 350 pistons, although now you can use 350 rods using custom pistons. Some blocks may need some clearancing at the bottom of the cylinder bores. Brian

Shouldn't the rotating assembly be balanced considering rods and cranks are being swapped? Block clearancing for the longer stroke crank?

If you have the $$$, by all means, balance. Some blocks may need some clearancing at the bottom of the bores. Brian

You should have the rotating assembly balanced and you need to use the 400 balancer and flywheel or flexplate. You may want to think about buying a balanced rotating assembly, all the parts will work together and you can get a good price in a kit. If you use 350 rods w/ custom pistons you my want to consider using a small base circle cam or you will need to check the clearance between the rods and the cam lobes. You can use a piece of bent coat hanger to gauge the clearance you need between the rods and the cam and block. Hope this helps.

Sean

Summit has their kits on sale right now for $960. I wouldn't go about this without balancing the rotating assembly unless you're just going to putz around town with it. But then who needs a 383 to putz around?

i have a 383 in my chevelle im thinking bout sellin but dont no but what about trading the 350 for a 400 an destorking it then u dont have to put the 400 stuff on idk im only 13 so i may be wrong

383 is an awesome engine. No cooling problems, lots of power and torque. You also will have to die grind a little clearence around the crank to make sure nothing touches inside (rotating assembly) at Hi RPMS. I don't know that much about building them, but let me tell you 'bout driving them. My 67 SS camaro will run 12's with foot in it, and get me 17 mpg with foot out of it. Runs cool in our California summers. I LOVE mine.

this is all been a great help ill be pullin the motor in the next week or so and you all have got very excited the kit from summit would that be balanced and incould what i need

Best would be to call Summit and ask. They're also on-line though their site isn't the best to navigate. I'd give them a call. You can get their number off the web site: http://www.summitracing.com Good luck and let us know how it turns out. Don

I have built some, and a 400 with 5.700" long rods. No big deal if anyone may tell you what to look for. Clearencing the base of the block where the rod bolts are likely to touch the block is easy and obvious. The not so well explained part is the cam. The upper rod bolt (looking the engine on a stand, frontwise, the bolt that is on top of the rod) WILL HOT the cam. By a small amount but will. 2 ways to solve it: use a decent set of rod bolts like ARP, grind a little amount of the bolt head, the part that is hitting the cam until you gain enough clearence or try to see a powdered metal rod used in GM 383 crate motor or in the marine 6.2 litter engines like the ones from mercruiser. You'll get surprised by the small amount required. As for balancing, it is a must do, no way to skip it. But the use of a steel crank, like in the marine engines allows internal balance. Remember thou that the 87 and newer sbc engines are not internal completely as long as they do have an extra weight on the flexplate or flywheel, but they are all the same for all the engines, and since they do have a 3 inch bolt circlr, they may not be used on an earlier engine, the ones that have real internal balance scheemes.

ok fellers

got the motor out taken it apart today
next question is allumin heads or just have my stock heads redone
do i gain much with allumin heads to offset the big expense also is there anything special i should have done to my stock heads if i decide to use them

thanks so much
the kid

This book by David Vizard talks about balancing and how to do some of it on your own. A real good book for the guy who wants to unlock some low budget horsepower. I really recommend this book.

http://www.amazon.com/Build-Perform.../105-9705360-7341231?ie=UTF8&s=books

Aluminum heads are great if your budget can afford it. Your 73 heads aren't worth too much (do you have a casting number of your heads?) They're most likely one of the first emission heads and are low compression. Probably have 1.72" intake and 1.50" exhaust valves. You'll spend alot of money rebuilding them and they'll choke down your airflow. If budget conscious, buy a pair of better iron heads. They perform just about as well as aluminum. Aluminum will dissipate heat quicker and are easier to repair if something happens to them. Some say that in higher compression applications, they tend to alleviate detonation problems. I personally use good casting iron heads. Some of the cheaper but good ones are the 040 castings which were 327 truck heads. Summit also carries their own brand iron heads for around $600-650/pair assembled.

Check out www.northernautoparts.com they have a 383 kit that is complete with crank,pistons and bearings. Also has a Crane cam and lifter kit.
Cost now is $474.99 all name brand parts. I have used several kits from this company.