Old school engines vs ls swap debate!!

[pontiacgp]

In our sportsman and pro late model due to the rules we used GM made in Mexico sealed 604 crate engine which is a SBC. The sportsman races were 100 laps and that engine was limited to 6,400 rpm which the car would hit about 3/4 way down the straight. The car ran hot many times at 260 degrees. That engine was never torn apart after we used it for 4 seasons and it's still on the track and still a front runner. The pro late model had a used 604 and that engine worked the same as the engine in the sportsman. The cost of a 604 is around $6,000 so it's relatively cheap for what you get.

 

[Hunter Urban]

I did a pole (keep 305, do 350, or LS) and most said 350 with some good information. Its called "Need some help/imput"

 

[autonaut]

I'm a good deal north of 350HP on my 383SBC... What stuff do you refer to as sacrificed?

It's stroked? Already there you sacrificed durability. That engine wont turn 200.000 miles without meeding a rebuilt. It's doubtful it will turn 100.000 miles without issues if your that high in hp.

Also, having a great deal north of 350hp you also have sacrificed streetability. Your engine will never idle 750rpm in neutral with a coin standing upright on the intake.

Most likely your fuel economy is also bad. And you require premium fuel.

Whare am i wrong? And how?

 

[autonaut]

It's stroked? Already there you sacrificed durability. That engine wont turn 200.000 miles without meeding a rebuilt. It's doubtful it will turn 100.000 miles without issues if your that high in hp.

Also, having a great deal north of 350hp you also have sacrificed streetability. Your engine will never idle 750rpm in neutral with a coin standing upright on the intake.

Most likely your fuel economy is also bad. And you require premium fuel.

Whare am i wrong? And how?

Almost forgot..

How many miles will your gen 1 sbc 383 take before oil start dripping on your garage floor?

I dont know about you guys.. But i have never seen a 2 piece rear main seal sbc turning 100.000 miles without engine oil leakage somewhere.

I feel some people refuse to let times catch up. Look at how the world looked like in 1955.. And how it looked in 1997.. Dont you think humanity somehow improved on the existing design of the smallblock in the years between?

 

[autonaut]

if my engine idles 750 with a coin standing upright on the intake something is wrong. If I build an engine to have fun with if it lasts 200,000 miles I wouldn't be disappointed.

Me neither.. But oil would be spilling in my driveway and garage and every single parking lot i parked the car will have a mark from my 100.000 mile engine.. Mercedes diesel engines are barely broken in at that mileage. LS 1/2/6 will be just fine and dandy at 200.000 miles if serviced good during their lifetime.
I doubt any gen 1 high hp +400 REAL hp engine ever has gone to 200.000 without issues. If your high hp gen 1 sbc engine does hit 200.000 miles cylinder 7 and 8 will be toast, mpg will be horrible, oil will seep from everywhere and if you remove the oil cap black fumes will arise.

Face it. As much as i love the gen 1 it has been surpassed by time and effort. There's no way around it. That doesnt mean it's not a great engine. And that money cant make it better. It's just not better.

 

[pontiacgp]

you need to do some research on 2 piece rear end seals. Apparently you don't know what seal to use or maybe you are installing them incorrexctly

 

[autonaut]

if my engine idles 750 with a coin standing upright on the intake something is wrong. If I build an engine to have fun with if it lasts 200,000 miles I wouldn't be disappointed.

If it idles with a coin standing upright something is not wrong. In the old days on stock chevy engines we used this trick to prove to our colleagues we could tune and adjust a quad and points ignition and set valve lash. The engine has to be well balanced to do so obviously. And well adjusted. No high hp gen 1 can do this due to cam specs required to reach the high hp.

A 400 hp gen 3/4 smallblock gets damn near close to do so. You probably could if you were a goid tuner with a laptop

 

[V8 Rumble]

Almost forgot..

How many miles will your gen 1 sbc 383 take before oil start dripping on your garage floor?

I dont know about you guys.. But i have never seen a 2 piece rear main seal sbc turning 100.000 miles without engine oil leakage somewhere.

I feel some people refuse to let times catch up. Look at how the world looked like in 1955.. And how it looked in 1997.. Dont you think humanity somehow improved on the existing design of the smallblock in the years between?

I think an 86-01 roller sbc would suit you well for what you're looking for especially if you're concerned with the 2 piece rear seal leaking. This thread will go back and forth with the debate as you know with no end. The tubo buick engine would be interesting but parts seem to be on the expensive side.

Or if you want efi with modern efficiency go with the ls since you mention about being caught up with modern times. I would do this second option if you don't have much of a budget restriction as I did.

I wanted to do an LS when I had to redo my engine last year but ended up getting doing another gen 1 sbc for the sake of keeping what I already had and not getting new mounts headers wiring etc.and other things associated with the ls swap. I searched and went back and forth on my decision and threads like these don't make the decision any easier. Or at least for me it didn't.

In the end you have to choose what you'll be comfortable with. This thread has a lot of great info from both sides LS, SBC and the turbo buick.

 

[autonaut]

you need to do some research on 2 piece rear end seals. Apparently you don't know what seal to use or maybe you are installing them incorrexctly

And if a 2 or 1 piece rear seal is all you care about when it comes to finding oil leaks you'll be hard pressed. Nothing i've said is wrong. 1 or 2 piece it doesnt matter much. Oil will find wayS out well before a gen 3 or 4 will have those issues.

 

[vanrah]

Greetings MotorHeadMike & all; Thank you for posting that excellent video on the Ls family. And another tid bit for OP (Boy 1), many of my closest friends would say that I'm very good at squeezing torque & HP from very few bucks. My education was auto engines & I worked in my dream shop during the early 70's. And again in a dirt shop in the mid 80's & in the john was the bosses library! So I'm reading one of the many auto books, the author is explaining bore to stroke ratio (5.7" rods) & valve shrouding. The testing had found that a 337 inch SBC would make the most power per cube of any engine (push rod) at the time. You ask how is this possible, well the 4.062 bore un-shrouds the intake valve & the 3.25" stroke seems to be the optimum for the 5.7" rods. But it costs more in todays dollars to build a 331"-337" than a 355" (.03" over) or 361" (.06" over) & of course it will make less torque than 350"er. My boss at the first engine shop would constantly remind me that an engine is just an air pump, like the guy in the video. So the heads are the key to any build. Once you decide on heads (team captain- quarterback-leader) then you can plan the rest of the team, compression, cam timing & what not. Dollar for dollar a 355"er with heads, cam & compression matched well with each other is the budget leader. In closing I should mention that my good buddy did build a 331 inch SB last fall with 10 to 1 compression, brodix street heads (180 cc runners?) & a modern hyd roller cam (good for about 5800 RPM). We fired it last fall on the test stand & installed it. So sometime this summer the rest of the car will be done & we'll be able to drive it, to say we're anxious would be an understatement. Good Luck, Bob Jr.