I'm curious on what kind of block "long/short" I have in my 98 GMC Sierra it has the 305 vortec in it an I'm lookin to go with a carberated 383 stroker what kind of block to replace it?

Asked by Jul 17, 2015 at 11:00 PM about the 1998 GMC Sierra 1500 K1500 SL 4WD Extended Cab SB

Question type: Car Customization

8 Answers

96,655

If you are going to go full bore stroker then you need the long block, it will come with the heads already installed and then you can chose your own intake/carb to bolt on. If you are going to do something like 4 valve heads or high compression heads then get the short block, then you can get the type of cylinder heads you want for preformance and the intake/carb to match. HTH

Thanks a lot much appreciated

400

Long block and short block is not a type boys.. a short block assembly just means a bottom end sometimes no cam shafts even.. a long block simply means assembled with cylinder heads.. Type well you have a small block Chevy

1 of 1 people found this helpful.
49,145

Long block is with cylinder heads, short block is with full bottom end (crank, rods, pistons, bearings, timing gears chain and camshaft). Complete engine has more parts on it than a long block.

400

Thanks for the info.. cause I don't know anything.. I'm glad this site is full of such gifted little mechanics.. lmfao I've only been fixing cars for 16 years.. but I'm glad someone's more technical than me..

400

I usually build them so I'm not up to speed on ordering a short block assembly.. lol

1,555

You're confused with "terms". A 305 is a small block. A short block is a partially assembled engine with no cylindar heads. A stroker 383 is made by combining a 400 crank into a 350 block. Small block sizes are 302, 305, 307, 327, 350, & 400, Big blocks are 396,427, & 454. Start with a 350 block & use a stroker crankshaft. Jeg's catalog has everything you need. Your 305 is low compression & low hp.

115

One other thing to consider. A 400 small block is the only Chevy small block that is externally balanced. The harmonic balancer, crankshaft, and flywheel (flex plate) are all balanced as a unit. But many aftermarket kits are internally balanced like a typical 350. You will want to know this so you have the proper parts rounded up when you put this engine together. Also, a 400 small block came with shorter rods than a 350 so make sure your kit comes with longer rods if you intend to rev the engine above around 5,000 r.p.m.'s. Otherwise piston skirts like to crack because of the stress the short rods cause. It's best to get all the parts at one source as a kit. That 383 is really just a 350 bored thirty over with a 400 crank dropped in. If you really do use a genuine 400 crank the main bearings are larger than a 350, so a machine shop will need to fix that for you. Also, plan on a long block, because the small valves in those 305 heads will be so restrictive you will never make any power. Hope this works out for you.

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