Inliners International Forums General Discussion Engines noob alert

So basically I've owned a 1974 Chevy nova custom with a 250 inline 6 for about 5 months and I've been wondering how much torque and hp you can get out of a inline 6? I like the idea of throwing your typical 350 small because you can get them to tear up the streets. I plan on having this car to be a daily/beater/cruiser.

If your gonna put a V8 in there at least do something less boring. 350's are cheap and over rated.

On the 6 cylinder side...really depends on how much time and money you want to spend. A Naturally aspirated Street 250 is capable of 310 hp and 280 torque. Or a mild turbo build could put you at 380 hp. Really need to know your budget and what you really want out of the engine. There's alot at your fingertips with this engine. Alot more than I think your aware. lol

I was think of a supercharge v8 still nothing to exotic and yeah it is cheaper to put a 350 together which does make me want to go in that direction but if I go with the i6 I'm willing to pay for some top dollar stuff.

I was in your shoes 27 months ago.

I fixed everything else on the car first. I wanted to get the car right before making it righter, right? So, anyway, I got her perfect in every way except the engine (other than a carb rebuild just because).

A funny thing happened. I won Camaro Nationals in Mild Modified last year. I knew it got attention at shows but I NEVER expected that!

So I started to like the old 6. So I bought Langdon headers and a 2.5" single exhaust. We'll them I went and got an HEI. Then a 4bbl...

You can see where this is going...

I can now walk right around a 327 with no problem. Soon I'll be chasing a stock 350. My goal, however, is to keep up with a big block car. I've decided to shoot for 450hp at the rear tires. Dependable 450hp.

So this winter I'm pulling the engine, trans and rear. Head is getting love. New cam, new pistons, new rods. 200r4. Eaton posi.

All in preparation for the next winter where I go EFI and add in a turbo with water injection.

It'll be fun to show up with a turbo 250 and have traction issues...

I was in your shoes 27 months ago.

I fixed everything else on the car first. I wanted to get the car right before making it righter, right? So, anyway, I got her perfect in every way except the engine (other than a carb rebuild just because).

A funny thing happened. I won Camaro Nationals in Mild Modified last year. I knew it got attention at shows but I NEVER expected that!

So I started to like the old 6. So I bought Langdon headers and a 2.5" single exhaust. We'll them I went and got an HEI. Then a 4bbl...

You can see where this is going...

I can now walk right around a 327 with no problem. Soon I'll be chasing a stock 350. My goal, however, is to keep up with a big block car. I've decided to shoot for 450hp at the rear tires. Dependable 450hp.

So this winter I'm pulling the engine, trans and rear. Head is getting love. New cam, new pistons, new rods. 200r4. Eaton posi.

All in preparation for the next winter where I go EFI and add in a turbo with water injection.

It'll be fun to show up with a turbo 250 and have traction issues...

Here's a pic from a couple months ago:

Damn that's crazy I didn't think you could get that much power out of a 6 I'm starting to lean towards fixing up me l my 6

It's more expensive to do than an 8. Fyi

....but you can do it in stages, unlike an engine swap.

I have 6,000 into my 292 and yes I went exotic as far as how it looks. lol But it will be a good dependable street engine that will walk around a 290 hp 350 if I want it to. As of now the expected power out of mine should be around 310 hp and 330 torque at the flywheel. A nice close ratio 5 speed behind it and 3.73 gears will make things Really Nice. Its cammed to have mid-rang torque and peak RPM around 5000-5500 rang....would have to dyno it to get exacts....Compression is 9.5.1-10.0.1 which is street friendly. Complete head work...1.94 intake 1.60 exhaust and lump ports installed with .030 shaved off the head surface. .040 overbore with lighter forged pistons with an 18cc dish vs stock 30cc. I did BBC roller rockers for smoother valve train operation even though I'm at a lift where non rollers would be fine. Cam specs 268H 219 @.050 .499 on a 110 lobe center. I went as much American as I could with this engine so parts were fairly expensive. I can still turbo this if I want to as well. Though for a driver....and mainly highway or backroad cruiser with occasional fun...naturally aspirated will suit me fine. I think the parts and machine work was around $4000 and the show pieces and carb an manifolds were another 2000. Your 250 won't make as much power as a supercharged 350 with equal boost....but if you were to turbo charge that 250 to as much as 10 pounds you'd have a Wicked engine.

I ess expecting it to be expensive but if I can get 300 hp out of it and still have that wow factor that would be insane. What are somethings I can do to improve hp and torque?

Well since you have a 250 you already have the "better" engine. Starting with the head I'd track down a 194 head. Already a compression booster there. Have it lump ported. Chamber relief will be require(I believe) to have 1.94 intake valves installed so look into that. Also 1.60 exhaust valves will be a good idea. Don't know if you shave the surface or not...Tom Lowe would be the one to ask...he has a Rocking 250 in his Chevelle wagon. Moving to the block....I'd do:
307 V8 flat top pistons.
Stock rods balanced and refitted with ARP studs and bolts. Or if you can afford a better custom set look into that as well.
A cam with around .550 lift will put you in the 300 hp rang. I think comp cams or one of Tom's cams has that lift.
Crankshaft balanced and ground.
Add a clifford or offy intake with headers and HEI you should see some 310 hp and 280 torque. Here's the video of a 250 similar to what I described.
https://www.youtube.com/watch?v=1p3-cAJrLCw

Thanks brother this is very helpful information. Why is the 194 head better than the original 250 head?

Its mainly for compression boosting. You can keep the stock head and have it shaved for more compression. Also if you get better pistons you can 0 deck the block and that helps with even More compression.

I think if you do a search here you will find some lively discussions about 194 heads. Most here stay out of the 194 head "discussions".

It is true that bolting a 194 head on a 250 will up the compression but when you start modifying them with bigger valves and then unshrouding those larger valves, so they will flow, the chamber becomes as large as the 250-292 heads. As a cheap quickie junk yard hop up dealing with two stock heads it was an improvement. With a built head?

The 194's can have the bigger valves and Un-shrouded and Still have a Much smaller CC area then That of the bigger chamber heads.

What are the numbers? What size valves and how much does the chamber have to be opened up? What is the final chamber volume? This has often been debated here but I have never seen the numbers.

If you would like to have your cake and eat it too there is an alternative to the 250's and their early 60's technology.

How about a 275/290HP from Stock GM inline 6 ... come visit www.vortec4200.com/forum1/ for details..

Yeah, a 350 is OK, but the LS engine is the way to go if you want to go fast & will out perform the old SBC's.

Then might as well go LS.

I still fail to see the point of this engine swap. The reason to build a 250 is simple: period correct or it cane with the car.