Stroking G-Body Motors

[fleming442]

I think it will still be cost prohibitive, even if you have a bunch of 5 yr old Asian kids casting the cranks.

 

[Max Headroom]

Most likely the Pistons would come out of the bore enough to hit the heads, you can't just throw in a stroker crank without matching the rest of the rotating assembly to it, one of the reasons they sell kits to avoid mismatching of parts

I will freely admit that, just changing the crank, under normal circumstance, the engine wouldn't even crank. Every piston would hit the head, break valves, etc. What I propose won't do that.

 

[Max Headroom]

So ask yourself this question, "Where did the LS engine come from?" Did Santa Claus bring it one year? If he did, he forgot to make a stop at my house. No, the LS came from a whole lot of engineers making improvements. A little here, a little there, a big one because of all the little progress. Presto zoomo, wave lilbowties magic wand here is an LS engine.

If you could start your horse power journey with a relatively cheap way to stroke your engine, why wouldn't you? Everything else you do provides even greater improvement than by itself.

 

[olds307 and 403]

The Olds 305 and 307 are both small bore. The only reason to do a 370 ci with the available 4" stroke crank in a 307 is for a H/O and 442 to be numbers matching. Problem is neither factory 307 head, the later 7A swirl port especially without a ton of work can support that many ci. An Olds 350 built by Cutlassefi with a 4.100" bore and 4" stroke, 422 ci with 9 to 1 compression, a small roller cam, 7A early 350 iron heads with just the bowls opened up with 2"/1.625" valves made over 400 hp and 500 ft/lbs with a way stronger solid main gas 350 block. There are a couple over 500 hp. The SBO is much less finicky than the BBO with far fewer bottom end failures.

 

[500/600]

Ringer

 

[64nailhead]

I will freely admit that, just changing the crank, under normal circumstance, the engine wouldn't even crank. Every piston would hit the head, break valves, etc. What I propose won't do that.

What are you proposing then? Building a 'stroker' implies swapping the crank.

I understand the budgetary concepts of every build. You're killing your time and effort with this - truly and non-sarcastically. The easiest and cheapest way to make a smog motor perform not like a smog motor is turbo. If your motor runs correctly, then a simple turbo setup in the 6-9 psi range will increase performance without hurting driveability for less than a $1000.

 

[GuysMonteSS]

Not in the accepted way of stroking. My approach is completely different.

Please,inquiring minds would like to know how you propose to do this ??
Guy

 

[UC645]

Well, this is quite the rabbit hole.

The only way you’re going to stroke a 305 without stroking it is to keep telling yourself you’re going to stroke it. You don’t want to swap crankshafts or bore one, that leaves offset grinding your stock crank. And how much can you really get from an offset grind? (If this hasn’t already been brought up)

 

[lilbowtie]

If you could start your horse power journey with a relatively cheap way to stroke your engine, why wouldn't you? Everything else you do provides even greater improvement than by itself.

There isn't a relatively cheap way to stroke an engine. It's much easier (cheaper) to work with what you have when on a budget. Now if you need to purchase a crank, pistons, or rods it might be food for thought. The engine in my Regal is a 70's 350. The short block is stock - never bored - and with a cam, 2.02 chevy iron heads, a Vic Jr w/ a 750 I'm around 500 HP, what more could you want. As Nailhead
said a turbo is an option.

 

[Max Headroom]

The Olds 305 and 307 are both small bore. The only reason to do a 370 ci with the available 4" stroke crank in a 307 is for a H/O and 442 to be numbers matching. Problem is neither factory 307 head, the later 7A swirl port especially without a ton of work can support that many ci. An Olds 350 built by Cutlassefi with a 4.100" bore and 4" stroke, 422 ci with 9 to 1 compression, a small roller cam, 7A early 350 iron heads with just the bowls opened up with 2"/1.625" valves made over 400 hp and 500 ft/lbs with a way stronger solid main gas 350 block. There are a couple over 500 hp. The SBO is much less finicky than the BBO with far fewer bottom end failures.

I am not proposing that this be done to every engine by every person. What I am working towards is a way to stroke a motor (conditionally, any motor) for a minimal amount of money. Everything you say in this post is true and EXPENSIVE. That's the point. Stroking a low compression motor is not magically going to add 75 or a 100hp without a lot of additional work but if you can add even 15 or 20 hp and then have a base engine worth spending low budget money on, what is the down side? You guys obviously don't remember what it was like to look through the Summit catalogue and dream of when you could afford to buy some of what was in it. I do.