How much horsepower can one get from an L24?

[dhayes5]

I have a '72 240 with 70,000 miles that runs like a top. I am not really interested (at least for now) in changing the motor to an L28.

How much horsepower can one reasonably expect to gain from doing the following:

1) A "mild street cam" Motorsport calls this the 2000 to 6000 rpm cam with good idle.

2) A '74 N36 260Z intake manifold.

3) '72 carbs with SM needles and grosse jets

4) A header and 2-1/2 inch exhaust (probably a super trapp)

Would this setup benefit noticably from a ported/polished/flow tested head?

I also have an '83 5-speed that I plan to couple to a 3.90 or 4.11 rearend. I understand that this will "wake up" the car as well.

Has anyone done anything similar? What was your experience?

[hmsports]

The 4.11 will give you a great hole-shot and lots of quickness up to speed... but you will sacrifice top end and you will spend a lot more time at higher RPM while driving down the freeway - the five speed will help with this a bit.

I'm not sure you will notice a huge difference just by changing the carbs and intake manifold.

The header and exhaust will make the biggest actual HP difference. Try to follow a couple of rules... try to get about a total of 126" total exhaust length - measured from the header flange to the end of the tailpipe. Also, make sure to have 9" of tailpipe after the muffler to help smooth the flow. I know you want a nice throaty sound to your car but about the best exhaust you can do is to get a stepped header from Rallye/Sport in Colorado (about $450 call Jeff Winter at 303-427-0510). This is a very tuned system that is a six-into-two (2-1/2") stepped design. Flowmaster makes a Y-collector that terminates to a 3" tailpipe. MSA has a six-into-one (2-1/2") header for about $150 which would be fine for a street machine instead. Either way, try to keep the tailpipe as straight as possible - which I know is just about impossible once you get to the back of the car - anyway, flowmaster also makes some great mufflers that are pretty cheap and sound deep.

Just my four cents worth.

[Zvoiture]

Paeco lists somewhere in the 200 range for their 'Stage II' re-build. That is with head P&P and engine B&B and with a 'Stage II' cam--which sounds like what you are shooting for.

DISCLAIMER: Go ahead and flame, because I would really like to hear some opinions of Paeco. BUT, don't kill the messenger--I am just reading out of a catalogue! I am not preaching the word of God! This is probably gross, and OF COURSE, this is their dyno! They also do not make very much distinction between L24-L28.

steve77