I guess I've been away long enough my current setup isn't known
At the moment, I've got a 318LA with magnum heads, dual exhaust, 998 trans and 8.25. I'll most likely rebuild the 998, I have a SG with 3.54s on the bench.
The A998 could have either gearset in it. Because you mentioned it, I will assume you have the 2.74-1.54-1.00 set. Then;
For a street-only car, to really have fun,I highly recommend more gear than 3.54s. And here's why.
The typical shift rpm for a typical 318 performance cam,is 5500, and the roadspeeds will be 43/77and 119. But more importantly the torque peak will be at about 4000 (maybe a little less, and the speeds there will be 31-56 and 86.
But MOST importantly are those first numbers; 4000@31mph, and 5500@43. both in 2.74 low gear.
You didn't mention the stall, so assuming it's around 2000, that makes for a possibly slow take off, until the Rs approach that 4000 rpm, which as a kick-down gear is great. What interests me, is first gear runs out at 43mph. And on the shift, the Rs will drop back to 3090. If you have cammed up your engine, and the LA is still at 8/1 compression......then Your cylinder pressure may be so low, that at 3090, your race is over.
>So what to do. Well, no matter what, it's gonna be a 2 gear run to 60, so you can either run less gear and a higher stall, or more gear. 2.94s would get you 60 at 6300. but you're gonna need a lotta stall to find acceleration off the line, with 2.94s, and using a cam that goes 6300.
>So after that, the go-to gear is 3.91s. Those, in second now,will get you 60@4700..The starter gear is now 2.74 x 3.91=10.71, almost too much. This would be like 4.37s with the A904. And no street tire in a stock tub will,withstand much stall with that amount of TM.
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>Ok so what if you had a 904. Well then the go-to 3.91gear will get you a 9.58 starter, a little more sane., and may work with your 2000TC. At the other end first gear now runs out at 48mph, and 60=4440rpm in 1.45 second gear.
So now you have another choice; 1)More power below 4440, or 2) more rpm in first gear. Or 3) a little less gear, a little more stall ,AND a little more rpm.
I'm guessing you'll pick option 3
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Option 1)
what you need to build with this combo is a stout engine with plenty of power at below 4440rpm, and pretty much who cares about after that, cuz the engine will rarely be asked to pull from there.In first gear,the engine is so lightly loaded, that it will blast to the shift-rpm no matter what small cam is in it. All you need is enough traction to not boil the hides, and enough stall to catapult you to where the power begins.
To that end, a stock Magnum is already pretty close to being the right engine.
but of course 3.91s are not hiway friendly.
On the flipside, 3.91s are a good gear for the 318 to trap in, 5000@98mph in third gear,in the qtr, and; 78mph@5800rpm in second, for the 1/8th.
In this case more power by cam may not be the best solution.
Here are some alternate solutions; More airflow by;more displacement, more heads, or more pressure.
Option 2) is the one you are currently pursuing
Option 3) is just option 2 but with gears and stall co-ordinated.
So since you have the 3.54s, stick 'em in,but wait until the engine is installed and tested,to pick a TC
Cuz if the engine comes in lazy off the line, it might want a 3000 or more stall. But if you bring the pressure up to 160ish with the street-cam of your choice, then it won't be lazy, and then a 2800 or less might be enough.
