SC notch

Hi all! I was wondering if anyone could help me. I have a 87 stock 5.0 with a paxton sn89 and full exhaust. I'm planing on getting a top end kit and was wondering which one I should go with and what kind other mods will have to be made. I'm running 6.5lbs of boost, with a topend kit what kind of hp am I looking at? I don't want a race car, just a badass street car. American muscle has a kit that is like $1600-1700 something like that. Is it any good? I'm probly gonna end up going with the trick flow. If anyone cans shed some light on this for me I would appreciate it thanks!

barnett468

hi,

unless you have hyper or forged pistons i would not run one at all.

if you only plan to run 6.5 boost max i would not spend the money on one because its a lot of money for littl;e return.

the last one i ran was on a 302 ewith around 9.0 static an comp xe262h or xe268h, cam, 185 heads and around 12.5 lbs boost at around 6800 rpm, 5 speed with 350 gears, it was pretty fast imo.

i ran it at 6 -7 lbs at first and it was a slug, hardly noticed it was there.

i would not buy a kit but instead buy afr heads and a cam similar to the one i ran but if you have efi on it or need to be smog legal, i can't be much help.

Duncan_GT

I wouldn't use a hypereutectic piston at all, waste of money IMO.

bluebeastsrt

Absolutely nothing wrong with a good top end kit like trick flow offers on a 302. The stock block can handle 400whp fairly well.

SC notch

Thanks for the replies and sorry for posting in the wrong place. I'm new to the site ( and mustangs for that matter) I see that Barnett says it won't make much of a difference to go with the top end kit... I don't see how that's possible to not make SOME decent HP... I'm running a stock 87 5.0 lx with and sn89 at 6.5lbs. I'm guessing I'm making around 260-285 hp.. First gear is killer! But second is lame. I'm still running a 3.08 gear soooooo yeah... I'm just wondering if ill see the hp gains I'm looking for (350-390) with this set up & should I do 3.55s or 3.73s???

barnett468

ok, i did not know you already had the charger.




That is not what I said however i can see that my post was not as clear as it could be and apologize for the confusion

What i meant was that i would not spend $2500.00 on a supercharger if i was only going to run 6 lbs of boost. i can put that 2500.00 elsewhere like in a stroker and stomp a 302 with a supercharger that only has 6 lbs of boost or i can do it with a 302.

6 lbs of boost will feel like the vacuum secondaries kicking in on a 4 v carb. it will be noticeable but uninspiring and you will wonder why you spent 2500.00 for very little perf gain.

if you run 12 lbs boost it will fell like the engine quickly gets more and more hp until it feels like around twice as much, lol.

instead of feeling like a 302 it will feel like a 400 after around 8 lbs boost.




This is very complicated.

in general, unless you get your static compression up to around 8.75 AND run more boost you will not get there.

you must also have a good flowing exhasust. if you need smog and catalytic converters i don't think you will get there.

if you run high boost on cast pistons they will likely turn into shrapnel.

you can not add 100 hp to a stock bottom end and expect it to live long.





you are on the right track, adding a kit will mainly raise the entire operating range of your engine. this means that it will have LESS bottom end. this means that in general your second gear will be even more lame.

higher rpm ranges require lower gears.

if you put 3.43 - 355 gears in it, it will feel like you added 75 hp to the engine.

if you run 3.73 first gear will be a granny gear and almost useless. with 3.93 gears it will be totally useless.

gears are almost always neglected/forgotten.






happy holidays!

Duncan_GT

^^^1st gear with 3.73's is useless?? How did you come to that conclusion? Many people, myself included, run 4.10's on the street and make use of 1st gear. I've also raised the rpm range of the motor and am still running a steep gear. Gears are torque multipliers, nothing more, and will vary depending on what you are requesting from the car

barnett468

Oh, it's not really useless imo however we have installed dozens of t5's and all the customers including my self prefer 355's. i could have worded my post differently.

typical tire size of 26.2".

i would say if one was a die hard street race they certainly might want something like 3.91 - 4.11.

this person has 3.00 and 411's would be a massive jump.

i think more info is needed before recommending any gears however from what he says it sounds like 3.43 - 3.55 will be a lot closer to the ballpark then 3.00's.

happy holidays

SC notch

I forgot to mention I do have full exhaust minus all the smog crap!