305 Vortec to 335 stroker

Jgoodyear4 said:

If that ends up being true, then I would definitely end up doing the swap, I’m not just trying to throw away money. The crate engine I’m interested in cost a little under 3k plus, sense I don’t have the necessary equipment, cost for a shop to install. So do you think having a shop do a rebuild + stroker in my current 305 would exceed that?

Click to expand...

I don't know what rates are in your area but around here mechanic shop rates are in excess of $100/hr, and I'm not sure what book time on an engine swap is, but you're not doing a straight up in/out swap. Your swapping in something that needs tuning and dinkering around with. Not all machine shops build engines so that puts you at a builders shop whether he does his machine work in house or sends it out. How many hours to assemble plus machine work and parts? Plus all the hot tank fees etc. The aftermarket stroker kits sometimes need some work and balancing will add another $250 to the bill. These stroker kits and/or cranks are not always ready to run out of the box. The rods sometimes are not spot on and the crank clearances are usually on the loose side. Have you even priced a 305 kit either with or without balancing? I prefer to have mine balanced locally with the harmonic balancer and flexplate. A crate at 2-3k starts looking like the deal of the century in comparison.

Another factor is your hole in the wall Napa type machine shops are working with 1950's wore slam out equipment so getting quality machine work can be a big issue outside of a higher end engine shop.

Which way to go depends on what's available and what the costs are in your area.

Jgoodyear4 said:

Thanks for the response. So I’m only asking out of complete ignorance, but could you fill me in on why 305s specifically like to spin fast and strokers don’t necessarily like to?

Click to expand...

The longer the stroke the higher the piston speed in relation the crank speed. Longer stroke also changes the rod/stroke ratios and side loads the cylinder heavier and why you see 6.0+ length rods being used in most stroker SBC's.

The 305 engines can spin at higher rpms because of less piston weight. Strikers add extra length to the stroke. Two engines being equal with one being a stroker, The pistons in the stroker must move in the cylinder at a faster speed if the rpms are also the same. At high rpms this puts enormous force on the pistons, rods, caps,bearings, and crankshaft. There are other things to consider like stroker pistons put the wrist pin closer to the top of the piston. Parts that handle these forces cost more money.
No matter what you do to the 305, you will have to do more to make up for the 45 cubic inches the 350 has.
I assume you are wanting the stroker for more performance. Switching to a 350 will be the fastest economical way. Then if you want more power, it is a great base engine to build on.

If you value keeping the original engine just add cam, headers and a tune and see how you like it. Shouldn't take too much to get to stock 350 power or so.

Hipster said:

It's 9:1cr so it's not a zero decked 10:1 quench build. It's a safe build for a truck that may pull some weight. You can move the cr around a bit with head gasket thickness.

Click to expand...

so with more cam, the compression goes down and so does early tq. im guessing the 9.1 is figured static. or is it figured with the cam they installed from factory. which brings more questions like ability fo fill the more displacement with an amemic stock cam?

Summit has a 350/383 block already clearanced and machined for 800$ check out white performance in Tennessee for your balanced rotating assembly.

You may also be able to save some money by having your 305 bored out to 350 specs. If your block is still good perhaps you could just do a cam, intake, and head swap for 350 parts.

JWS6196 said:

You may also be able to save some money by having your 305 bored out to 350 specs. If your block is still good perhaps you could just do a cam, intake, and head swap for 350 parts.

Click to expand...

Um no, a 305 won't take a 350 bore

Same stroke, cute little bore...

Jgoodyear4 said:

Has anyone here stroked a 305 (Vortec specifically), and what were the horsepower results? I have done the research and I understand I could swap into a 350 to make more power, and I am also considering that. However, I would be interested in doing a stroker on my 305 Vortec depending on the results. It would be slightly cheaper than swapping in a 350 crate, albeit less powerful for obvious reasons. If the stroker plus a few other mods makes enough power for me, which is somewhere in 300 hp range, I would value keeping the original engine in my truck. Seeing as the Vortec starts with 230 hp, it doesn’t seem crazy to think I could get it to 300 by stroking, installing long tube headers, and getting a tune by black bear. If you have any experience with this, please let me know, thank you.

Click to expand...

383 stroker will get you exactly what you want. But I nice 350 a slightly bigger cam with supporting mods can too. 305 would just end up costing you more and you'll be disappointed. I've found out the hard way.