old n42 block/head vs new f54p/79

[malibud]

Ideas ?

I have a 72 240z, w/ stock n42 engine/block elct. ign., headers and su carbs. the compression is about 150 across, hot, there is a small oil leak at the head above #3 cylinder but runs good.

I also have a f54 block with flat tops bored .20 over newly rebuilt 10:1 comp. with coated headers and rebuilt sus carbs, everything new dist, water/oil pump, etc.

Question ... HP gains would it be worth the engine swap ?

lets say hypothetically that I could sell my new set up for $1500-2000 range would the money be better spent with a head gasket and triples ? with dished pistons in the old n42?

would like to go turbo but am scared of the money pit and complications

I like the car. lowered , unknown shocks and Toyota brake upgrade but could use a little extra not wanting a small block

thanks '

Dan

[madkaw]

That's a close call. The 54/79 combo is definitely a better NA combo. A more modern combustion chamber = more CR=less detonation=more timing=more power.

You could sell the old motor as a complete runner and save your pennies for triples on the 54/79!!

As far as turbo charging, neither set-up is that good, so planning a future based on that will be tough. you would need to aquire a p-90 to put on the n-42 for future TCing

[malibud]

thanks, I figure it would be easier to go 54/79 route. curious about different set ups . so ball park rear wheel hp numbers 54/79 stock was 135 i figure maybe 150 on mine (bored, shaved, headers, su carbs, stock cam) add 15 hp with cam and 15 with triples.

The big question is would I really Feel any major difference ? between the 2 engines or upgrades there after .

i see you have a built 2.4 any idea of rear wheel hps?

I have a close ratio 5speed w/ 3.9, Does the LSD make that much difference ? it seems to me that I almost want to have sway bars first.

Thanks

dc

[madkaw]

HP numbers are all over the place when you start digging deep into these forums. I think Jeff is getting 180+ on his L28 with SU's. I saw 155 RWHP on my L24 with SU's, but no dyno on the triples. I figure 180 with the Mikuni's.

"feel any difference" relative to what? To each other with the same mods? With a light car 20HP will feel different and being able to run full ignition advance with a 79 head might be 20hp difference.

There are some good threads at Hybridz that talk about heads and there potential. The P79 is an excellent street/mild race head. Shaving and bigger cam give good results.

The 42 is a great all out head but will need quite a bit of work to get there.

I don't see mention of a cam in either engine. It's all in the head on these motors!!

[malibud]

Thanks for the info i came across a turbo car in my area thinking I may pull the trigger. he said it would idle but when you stepped on the gas it would die the price was reasonable if nothing else part out. Now just to find the 75-76 gas tank .