Hi, I am new here and was wondering what step I should take next to upgrade my cobra. I am not sure with the upgrades I have (you can read them from my profile) if I should stroke it to a 393/408 or supercharge/turbo charge it. I like the idea of running all engine with stroking it, but am not sure what sort of HP gain I will get. I am also wondering if i do both in stages, which one should I go with first? Thanks for the advice
is it rough on the engine to stroke it to a 408? im not sure what sort of wear it puts on it. im sure it wouldn't be as bad as a turbo as far as breaking stuff goes. im also wondering how much my gas mileage would go down? i only get like 12 mpg now with the cam i have in it and dont want it to get too worst.
It really depends on how the 408 is put together. There is no easy answer. I had a good friend who used a Dart block, built his 408 Accel DFI, lots of goodies. First time out he ran a 9.76 at 138 mph. So it depends on cam, heads, and what it is you want to achieve. What is your goal?
im looking to be around 500RWHP and matching torque. I was told that I would probably have to change the cam because it wasn't big enough, but I think the cam I have now is Huge and don't see why it wouldn't support 408, or even a 393. Ron, maybe you could take a look at my profile and tell me if i have the support, ie. heads cam etc. for a 408/393 stroker. Thanks.
I currently have a 408 in one of my cars. I did not do any of the mods myself, because i traded a car for a car. I have $10,000 dollars in receipts for just the engine in this car. Components would take all nite too list. Anyway, after all that, the engine dyno was 529 HP, 483 HP at the rear wheels. Have done some more mods since then, but no facts or figures yet. Oh ya, this is all motor..........maybe a wet shot too come........
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'92 LX Coupe 5.0, Stock Ported Intake & Heads, C & L CAI, BBK 75 MM T/B, 24# Injectors, Lunatti Cam, Hedman Long Tube Headers, Flowmasters, Tremec 3550, Spec Stage 2 Clutch, Moser 31 Spline Axles & Spool, UPR Upper & Lower Control Arms, Lakewood Shocks, Auto Meter Gauges, MSD 6AL, Line Lock, Rollcage, Subframe Connectors, Nitrous,Weld Draglites, Drag Radials,4:56 Richmond Gears.
OK. One of the hardest questions to answer, and one we always ask..what is your ultimate goal. What will the car be used for? Daily driver, street/strip or strip only. Setting a horsepower goal is good, but you have to be concerned what sits behind the motor as well.
BTW, the cam you have is a mild sorta lumpy street cam. Almost identical to the one I had in my old 306 CI. 284/292 .510/.510.
Let me check out some things once you let me know what the car will become.
I want around 500RWHP and matching torque. I was thinking about going the nitrous route because to s/c it I would have to lower the compression and get a s/c friendly cam. And If i have enough mods to support the 408/393 stroker I will do that, but if i have to change a bunch of parts out i prolly won't go that route. smacking on a $700 wet nitrous kit that can give me 150 instant HP is looking like the route I will take. This car is going to be mainly a street car but I will take it to the track here and there. Basically a summer/weekend car.
Do you think the stock T5 tranny will be alright supporting this?
To answer the T5 question first..the 1983-1989 V8 T5's are rated at 265 lb.ft. of torque, while the 90-93 T5's are rated good to 300lb.ft of torque (93 Mustang Cobra T5 is rated for 310 lb.ft.) The TKO is rated at 450 ft/lbs, so if you want 500 rwhp we will have to go beyond that. 500 rwhp is roughly 600 fwhp figuring a 15-20% loss through the drivetrain. So now we need a new transmission. You could run a turbo or supercharger, as long as you kept the boost down. Nitrous could be an interim solution but there too, the T5 won't last long.
I have to stop by and see my engine builder tomorrow, so I will lay out your request and see what he says, and what kind of cost you might be looking at. The only other negative thing I saw were the KB hyperutectics.(I assume since they are KB's they are hypers). Not very nitrous friendly. Very minor error and they will be gone.
i have a engine on the dyno right now 566hp 531tq 4.o60 bore 4in stroke trick flow street heet heads soild roller 550 lift 276at .050int 286exh 112 center heads are box stock 91 pump gas. 707hp on nos 150 sniper 112vp race gas.very streetable!
Hey the route with nitrous is definately what you probably want to go if you want to keep a good driver that wont eat up any more gas. Dont worry too much about the KB pistons i have a set in my car and run it on the bottle all the time, just make sure everything is set up right and dont lean her out.
As for between the supercharger and stroking, for cost effective the supercharger is the way. And you probably will make more power, just keep cramming more and more air in there. Normal atmosphere is like 14 lbs i believe, right? so if you put fourteen pounds of boost into the motor that is doubling the cubic inches of the motor......theoretically. Everything isnt 100% efficient so it wont quite work that way, but you get the idea.
STROKE or TURBO/SUPERCHARGE 
