well? can u. i have a friend who has another friend that says that he has a stroked and bored 305 block and now it is a 350. can this be done with a stock GM 305 block. i say it can't be done or why would we have 305s, nobody would, theyd all make them 350s. thanks.

 

The chevy 350 has a 4 inch bore and a 3.48 stroke. The chevy 305 has a 3.763 inch bore and the same stroke as the 350, they have the same crank.

The 305 is cast differently than the 350, if you were to bore it out to a 4 inch bore you would hit water passages I'm pretty sure.

You could stroke a 305 with a 400 crank, this would make the stroke 3.750 inches and displacemnt 333. Then bore it out .100 over to make a bore of 3.863 inches and a displacment of 351. I don't know if this is possible.

If you did this to get the 350 cubes it still isn't the classic 350 chevy, it would be a mess is what it would be.

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1989 Pontiac Firebird Formula W6S LO3 TBI 305.

1985 Camaro IROC-Z LB9.

 

PLAIN AND SIMPLE...NO.
you cannot bore a 305 to a 350.
even if you could...it wouldnt be a 350...itd be a 350 cubic inch 305. haha.
you will bore right through the cylinder walls if you bore that much. NO. noone has ever done it nor will anyone in the future. your friend is either lieing or the guy who he got the engine from lied to him. if anything its probably a 327 stroker or something.

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Rick
90 Camaro RS 305 TBI
400 on the way!!
TH700-R4 with Trans-Go shift kit
MacEwen Motorsports White Gauge Overlays
K&N Filter Charger (wooohooo)
GTS Headlight and Taillight covers
5% Limo Tint all around
Classic White Chevy Bowtie sticker on rear window

Man if my camaro were a rice-rocket all those mods would give me what...easily 50-60 hp!!!

 

This should be a FAQ. It keeps rearing its ugly head.

 

If you stroke and bore a 305 You get a 351, why anyone would Do this is Beyond me...



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85 Z28 - Daily Driver
60 Ranchero - Project ( Money Hole )

 

I don't think anybody would. I think I'd stoke one, but then I think why not just go for a real, less expensive 350.

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1989 Pontiac Firebird Formula W6S LO3 TBI 305.

1985 Camaro IROC-Z LB9.

[This message has been edited by Keith5 (edited November 07, 2000).]

 

you could use 4" sleeves i think, but again why? the 305 and 350 cranks have the same stroke, but are differant due to the weight of the rotating assembly, or in other words don't interchange cranks.

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-=ICON MOTORSPORTS=-
1st & 3rd

 

no, dont bother, just get a 350?

 

I argued with my friends a while back that 305 and 350 cranks had to be slightly different. I figured that 305 cranks were cheaper made. They proved to me that they were the same crank. Do you have any links to send to prove that they are different? I'd like to know for sure one way or the other. I think I've seen in parts catalogs 305/350 crank as the same part number.

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1989 Pontiac Firebird Formula W6S LO3 TBI 305.

1985 Camaro IROC-Z LB9.

[This message has been edited by Keith5 (edited November 09, 2000).]

 

Your friend's friend is mistaken.

The 305 bore is .237", almost ¼" smaller, than the 350 bore. Most of the time a 305 will not bore out to even as much as .060" over, much less .237". There isn't that much metal there to bore out. You cannot turn a 305 into a 350.

The cranks are the same casting, but are balanced slightly differently to make up for the different reciprocating mass. They will often interchange though, especially if the assembly is being balanced anyway. So technically, in factory motors, the cranks aren't the same; but that doesn't mean that they're different either.

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"So many Mustangs, so little time..."

 

the cranks might be physically the same but I think they are at least balanced differently. The 305 piston is about 100 grams lighter than the 350 piston.

 

Absolutely! The only difference between the 305 and 350 cranks is balancing (they even share the same part numbers sometimes). How can you tell the difference? Easy, get a straight edge (ruler) and lay it flat (or try to) on the counter balance "notches". If it lays down flat, touching all the counter weights, it's a 305. If the straight edge cannot lay flat and touch all the counter weights, it is a 350. Simple eh?

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George P. Lara
1994 Z28 LT1 T56
1984 Z28 High Output
Member: SCCA, SCFB, SC3GFB

 

Thanks for that info everybody.

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1989 Pontiac Firebird Formula W6S LO3 TBI 305.

1985 Camaro IROC-Z LB9.