I'm sure this has been discussed in the past, but I'm knew to the forum and havn't seen any posts on the subject. I'm wondering what everyones opinion is on boring or stroking for increasing displacement on an LT1. I'm a diesel guy by trade but I would say stroked would have more torque and bored would rev higher - faster. Help me out Auto guys.

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1995 B4C, LT1, SLP Ram air hood and intake, SLP headers w/ Loudmouth exhaust, 3.73 rear, Compcams 1.6 RR.

 

Are you serious? You claim to be into diesels by trade and ask a question like this? You just pumping fuel or what?

The practical overbore limit is .030, almost meaningless, stroke is THE way to increase displacement BUT that is not where power is made, heads are where power is. Most guys who think displacement is the key endup making less power than good heads/cam stock shortblock setups.

 

The previous answer is where it's at. I would just add that some people do go more than 30 over on a stock block. To be certain this is feasible, the cylinders need to be sonically checked for thickness though. Otherwise it is a gamble. Still, as was pointed out, the displacement gains are relatively small. A 30 over 350 is a 355 (gains 5ci) and going 60 over gains just a touch more than 5 additional ci to make a 360. Adding 0.25" to the stroke of a 350 takes you to 377 (383 at 30 over) and a 3.875" crank get you to 390 (396 if 30 over).

Of course, to make you of that you need to upgrade the heads, cam, intake, etc. Otherwise, while you will increase low and midrange torque but not raise the peak.

Rich

 

A coworker has a 350 block w/4bolt mains bored .60 over he's willing to give me to make room in his garage. Should I take it or use it as a boat anchor. Once agian, hat's off to you gas guys, in diesel we just bump up the fuel pressure and make some timing adjustments - most of the time that satifies most truckers.

 

take it if hes giving it away

 

so is that all you need to know in order to claim to work on diesels by trade?
That's scary. Makes me wonder how many dealership/shop mechanics are the same way.

 

I'm just a high paid parts changer.

 

He came here to ask a question not for people to give him hell........that's not a good way to welcome someone. It doesn't matter what he does for a living or what he should or should not now. He didn't come here to ask if anyone thought he was a good diesel mechanic or not, just wanted to know the anwser to what YOU thought was a easy question......lighten up! Sorry there are people who don't know how to act on a public forum. Good luck with the block.

 

HE seems to be able to take care of himself, and has a good sense of humor. YOU should learn a little from him on that.

 

The LT1 does not use the old 350 block which is what it sounds like he has.


Far as being a "high paid parts changer" sad thing is today that describes probably 98% of technicians, so very few of them actually understand the procceses going on it is sad.

 

That is true also here on the other side of the world...

 

Diesels are very complicated, computer controlled, high performance engines from the get-go. I could sit here and discuss diesel performance all day. The truth is that in the diesel world, trying to do things such as boring out the engine or changing a crank to increase stroke just don't happen because aftermarket parts are not available. Diesel tech's therefore do not get much experience in upgrading engines further than changing a few hard parts and "re-mapping the computer". But this is not a diesel forum so I'll shut up.

 

Sadly within the confines of an LT1 block the bore is very limited, but on the traditional SBC the aftermarket blocks can be bored out quite a bit (not like a big block .090 over or anything). Any amount of larger bore though even a .030 overbore will help unshroud the valves in the head allowing better flow.

Most people who increase displacement forget to increase the ingoing nad outgoing air along with the displacement. This makes alot of people beleive that increasing cubes is worthless over changing the heads on a smaller motor.

Optimize a set of heads and cam timing on more cubes and your potential to make more power is directly proportionate.


Otherwise they wouldnt limit cubic inches in 90 percent of the racing classes.

 

((Sorry this is so utterly off-topic, but 1995ospb4c since you are a diesel guy, can you explain how this type of performance is possible on a diesel? http://videos.streetfire.net/video/4...4500e9c7c9.htm ))

 

I'm with you on this one.... unfortunatley we have at least one member who feels that the way to help people is to violate board rules by insulting them. Its a frequent occurance, and corrective action is going to be taken.

Fortunately "1995ospb4c" has the maturity that another is lacking.

None of this is necessary.