Well I pulled the trigger and started a rebuild of my tired L48. Pulled the engine a couple of weeks ago (pics to come), and got started.

I've done alot of reading here on the subject and choose a direction.

My goal is not a race engine/car but a reliable fun street motor/driver. I definitly wanted to build more horsepower than the wimpy L48. Here's where I'm going parts just arrived:

Scat 4340 stroker crank
5.7 rods (stock style w/press fit wrist pins)
Bore .030 over
Speed Pro Flat Top Hypereutectic Pistons
Hastings Moly Rings
Clevite main rod & cam bearings
Double roller timing set
#12-210-2 Comp cam:
1500 - 5500 RPM range
Lobe Sep -110
Duration - 268 / 268
Dur @ .050 - 218 / 218
Lobe lift - .302 / .302
Net Valve lift - .454 / .454

Comp Roller Rockers w/lock nuts 1.5:1 Ratio (same as stock)
Copm Hardened push rods
Elgin valve springs - good to .490 lift
New Flex plate
New balancer
Melling Hi Vol oil pump
Fel Pro gasket set
Rotating ***'y to be externally balanced
Long tube headers to true dual exhaust

I'm staying with stock heads for now (budget) but will give fresh valve job and port. Still haven't choosen an intake (suggestions welcome)

I love this forum and the depth of knowledge here so PLEASE tell me what you think good or bad.
Thanks

 

With the stock heads, I'd put you in the 325 - 350HP range.....
A far cry from the stock 195HP L48

 

Dart has fair prices on heads I would forego that valve job and porting and look into a set be it them or another company's aluminum heads .

 

I had a similar motor many years ago...stock crank and forged pistons, 4 valve releife form speed pro...

compression was about 8.5:1, and the cam was very similar, except .461 on the lift...with a set of 882's for the heads...made about 300-310HP, if I remember correctly...

 

I'd consider a 383 crate motor even if you need to save up a few more dollars.

Belay that. I see now that you already have bought the parts. GL with the build.

 

Not really. The L48 was rated in Net HP. 325-350 will be gross HP or maybe 250 Net.

 

I've never seen numbers like that for a L48?

 

he's saying the combo will make around 55hp more than the stock engine.

 

Exactly. Can't directly compare gross to net numbers.

 

What ever the power level really is, the car will be sluggish from a standing start with the 3.08 rear (assumed since the car is apparently an automatic) and the stock torque converter.

 

The real power is in the heads. Are you SURE you can't swing an improvement over the stock ones?

 

383 with that cam will make a torquey driver
Good heads when you can will sure wake it up

 

As mentioned, I wouldn't put a penny in the stock heads....I'd get a set of just about anything...it would be better. Iron or aluminum...unless you get the cheapest import ones you'll be way ahead.

Then once you get decent heads, choose a better cam.


JIM

 

Do the heads.....Big Power means Air In and Air Out.....Everything works together so if you have big pistons, Cam but no way to feed the beast it will starve. If you restrict the exhaust you are going to slow the purging of what you feed it.

Dart, Pro-Filer have affordable heads ready to go.

I think a set of 2.02 heads run a little less them a grand.......I paid close to $1200 for heads on one of my Harley's.

Simple to do now and not have to redo it later.

Just my thoughts,

Karsten

 

I agree - go with better heads.

 

Scat 4340 stroker crank, so we're talking about a 383 here, right? I'd guess around 350 horsepower with the stock heads, and maybe around 1 horsepower per cubic inch with a good set of heads. I am definitely not an expert, by any means, so this is purely a WAG.

I agree with those who say a good set of cylinder heads are very important. When you get around to it, you will probably notice a distinct difference in power with better heads, and wish you had done it sooner! You do the best you can with what you have available, though, and it sounds like you are building a good base for later upgrades, which is a move in the right direction. Doing a head swap later isn't that big of a deal, relatively speaking.

Scott

 

They are after all, large air pumps. Air in, air out.
Heads and exhaust = big difference

 

depending on compression.....
10:1 350h 400tq
8:1 310hp 300tq

my guess:-)

 

Paul, what are you doing hanging out here? You should be out getting the 427 running!

 

v2racing
Wish,,,, im stuck here at work,,,,, im firing her up this weekend... :-) very excited, and.... a little worried:-!