So building a 400 + RWHP 2v NA.... how feasible is it and what it takes....
Based on Head flow numbers, blocks available and current results posted over the years, getting a 281 cu 2V modular is extremely difficult to hit 400hp NA....
This takes a high compression, full bolt ons, other Drive Train improvements, big cams, and a Short runner intake and may not be the best set up on the street.... Hitting 380rwhp is possible with a normal runner intake but takes a lot to get there as well but has a grear drivable power curve. Now that we are 4 generation engine platforms past the 2v most have stopped experimenting or trying to find the right parts to get the 2V engines to run with today's mustang engines.
Since there are soo many 2v's produced and most just throw a power added on them but there is always the crowd that like to run naturally aspirated.
So what does it truly take to hit 400hp on a street driven 2V NA and how far past this can you go.
1-set of great flowing heads - I have seen as hi as 408rwhp on 281 cu shortblock but with a high flow intake and you trade that off with TQ... I believe that setup was a carborated set up with Teskid block 11.5 to 1 CR on pump gas, Victor Jr manifold but only had about 340 tq with 408hp... not bad but I would like to have TQ over 400 as well..... Heads need to flow 260-300 cfm to get to 400 NA so a stock TFS head is needed at minimum but ported 185s or 195 Rs will get you over the hump with larger displacement...
2- larger displacement - you would need a stroker kit, 5.0 Boss FRPP block or 5.3 Boss FRPP stroker with TFS heads to get there with TQ and HP over 400 to the tires...
3-cams.... since most aftermarket parts for the 2v are based on the 281 platform, not many have ventured to see what HP you can get out of increased storke, larger Cubic Inche motors.... the heads were designed for 281 but the TFS heads outflow the capacity of the 281 or around 360-380hp tops on the stock bore... Cams for larger bores are not noted as a stage 4 cam in a 281 actually performs like a stage 1.5 na cam in a 323 stroker.... 42 cubic in increase from a 281 to the 323 5.3l needs to breath better up top but never caught up with the 2v as newer 3v and coyote platforms were much better out the factory... Knowing the parts available now you can do a 2v build from 400 to 500 if you have the time and money.... one noted 2v claimed 500 hp at the tires on a mustang dyno with a 12.5 cr on pump gas with custom ported 33cc TFS heads (Not R), fully customized build with part matched to .002 grams for internals and cams, custom profile cams, Victor Jr intake with Fuel injection set up.... I believe that is possible with the heads flowing around 280-290in and 220-230 exhaust ..... this was on a stock bore with a stroker crank so 5.1 L 301 cu engine with 12.5 cr and 4% increase in HP per 1 pt cr it was impressive...
Cams are limited on stock heads for lift to around .550 lift with PTV clearance issues.... the TFS stock heads are .580 no problem and can go further with some valve train upgrades, and the TFS R heads can go to .650..... largest cams advertised by any shop are .575 lift so custom cams can provide a nice bump in HP on the top side depending on how much you can get the heads to flow..... Think LS motors and how much power they put downn on a 5.3l engine...they have heads now that flow 390cfm.... Not sure what a max flow you can get out of a TFS ro TFS R head but 310 I would think would be feasible with stainless steel vales, upgraded guides and seats...etc... I know MHS and Fox Lake have some products that would hit those numbers but for a cost...
4-Compression- how far can you take the 2v in compression ratio?... Well I know that 11.5 to 1 on a custom tune can bang all day long without issue...most think old school around 10 to 1 but since these cars don't have iron heads and everything is aluminum, along with all improved cooling systems in today's standards... 12.1 I think is safe... as noted above on the 500hp na set up it was 12.5 to 1... I don't know if the car had any issues on pump gas with detonation but would need more info on pushing that far... Technology today for Ford has 12.1 CR factory with VCT.... even adding and tuning superchargers with that high CR is safe as they can change the dynamic pression using VCT... awesome stuff...
So how far can you push the CR on the 2v? Well based on a lot of reasearch, around 11.6 to 11.8 to 1 CR is safe with commpression around 195 psi per piston.... that is the safe max threshold for 93pump gas...
With all the above variables in mind, here is built 2v with a 5.3l Boss FRPP block dyno chart below with 38cc TFS heads stock, stage 4 MSH cams, full exhaust, bullet intake... this car was at the threshold of 400 to the tires and tq so the added Cubic inches caught up with the stock TFS Heads.... this was 11.3 to 1 CR.
Using this as a baseline, add in ported heads, Meizure electric Water Pump, Aluminum DS and flywheel (not sure if he had either) a PI Intake with
BBK 78mm combo or try to port/extrude hone the Bullet at least (I have tried the bullet on my car and it had the same HP and TQ as the stock PI with Accufab Plenum and 75mm TB -exactly the same) I tested the
BBK 78mm combo on the PI and picked up almost 10hp and 12tq over the bullet and accufab set up fyi....
Getting the CR to 11.66 to 1 would be the goal so in total, NA 420hp/tq max with the PI set up.... that would be with 2% more HP with the slight bump in compression to max things out.... with an R Head and custom cams with .610 to .625 lift you could add another 20-30hp on top of that.... Now there are a lot of 440hp TFS R headed mustangs running the Victor EFI set up but TQ dips down to the 360s and I believe you can still get to 440 with the right cam lift profile and a great port job....You don't see this much but MHS noted that is the average for their racers, so assuming NHRA class guys...
With my goal, I will be using my ported stock TFS 44cc heads, 11.66 to 1 set up with the 5.3l Boss FRPP stroker, MSH stage 4 cams... pretty much the same below except I have the drive train parts, ported heads, and Electric water pump and better intake combo....
Seeing most gains in Cubic inches or about 1.2 to 1.5 more HP per Cubic Inch... the stoker is worth 45-55 more HP and 55-65 more tq... plus the dyno chart below for my set up had PI cams (VT Stg 2.5) in the TFS heads so exhaust timing was off about 10 degress... gonna be a fun little buid as all I need now is the 5.3l short block...