It all comes down to the octane (including alky), and the tuneup and traction. There is a big difference between pump gas and street tires compared to race gas, race chip, and slicks, up to 1.5 seconds worth. On 93 octane (no alky) with a bone-stock longblock, pte54, 72's, and CAS V2 frontmount I've gone 12.15 at 110.5 at 4060 lbs going down the track, with drag radials and a personal best 1.7 60'. I think that at my octane I'm about maxed out, since I put on a GT67 p trim turbo and only dropped to 12.02 at 111 the one time I've been to the track so far. I expect that with good iron heads I could drop .4-.6 seconds (well, add 4-6 mph and given traction drop the et), and with out of the box gn1's maybe .6-.8 seconds and 6-8 mph total. Going to 100 octane fuel or alcohol injection with 93 should give me between .2 and .5 seconds and 2-5 mph with my current stock heads (I think less than going to iron heads based on the boost and timing I'm already running, and what I think I could run with alky). So if you want consistent low 11's on slicks you should be able to use a stock shortblock with GN1 heads, 66-ish sized turbo, and frontmount, and run either 100 octane or 93 with alky injection. The GN1's would make it easier but with tuning you should be able to run under 11.50 with ported iron heads if that would satisfy you (guys, before everyone starts telling me how they ran 10's on iron heads, remember I'm limiting the octane to way less than C16
). The other option is a combination that gets you low 11's on C16 but is really an 11.8-12.2 car on 93 octane/alky for everyday driving, which basically lets you stay with iron heads for sure and maybe not even ported ones.
The real thing to think about is that transmission. Based on a few of my experiences and watching several friends go through this, I think that at the low 11 level a 200-4R only has a limited number of passes in it before it either breaks a hard part or needs a band and/or clutches. Everyone is free to pick their own number but I think that that number is between 200 and 400, and I define a pass as going WOT for at least one shift. Slowly rolling into it in third gear so it doesn't ever downshift, and you don't let it upshift into OD, isn't a pass as far as the trans is concerned because it never had to handle a WOT shift. For a track-only trailer queen that makes 5 passes a weekend for the summer, that's maybe 100 passes a season and the trans could easily last at least a couple of years even in the 10's. For a hard driven street car where you mash on it every freeway on-ramp and at least make a wot 2-3 shift, plus any actual racing, I bet you can rack up 30-50 passes according to my definition in a hard weekend and suddenly that 200-400 passes comes up fast. Now you are dropping the trans every two or three months and starting to put your trans guy's kids through college
. Yes that overdrive is great, but unless you build your own transmissions a TH400 starts to look real good after a year of this (or maybe CK Transmissions AOD conversion if you really want OD). Installing a TH400, including the trans and converter, costs less than one good high performance 200-4R rebuild ($1500-2000 depending on how much you do yourself).
