Need 375+ RWHP naturally aspirated

[Marz]

Hey guys I got a challenge for myself. I have built 2 blower motors before but now I want to go NA. My goal is 375+ RWHP. I want to go with a 306 or possiblly a 331 CHP StreetFight motor or DSS ProBullit. What compression works best , timing, parts etc. I also want to add a 100-125 shot of juice at the end . Will be running 91oct. pump gas.

Any info will really help.

 

[rj95svt]

You will need atleast the 331 maybe a 347 to make that goal. A 306 isn't practical for that kind of hp. My suggestion would be CNC'd TFS 185's, holley systemax intake, and a custom cam with all the right supporting mods including 1 3/4 long tubes, 36 lb injectors, 75mm TB, and a good maf. Thats just my suggestion. Others will probably have some good suggestions.

 

[302RollinHard]

351 swap. 375hp is easy like Sunday morning then.....

 

[Marz]

What kind of compression should I look for?

 

[Marz]

What are practical RWHP numbers for a 331 and let's say 10:1 comp.

 

[Daggar]

This is a "Guess My Weight" kind of thread.

--moved to Talk--

 

[GTOreturns]

I believe Keith Black makes a 375HP 306!

 

[fivespeedsteed]

ive done some looking into high hp small block NA motors, you can get over 350 with a 306 or 302(same thing), you have to have a good set of heads, and nice intake mani, and custom cam. compression at 10 is probably good, but i think i read somewhere that another 1:1 (ie 10.1:1 to 11.1:1) is about 30 hp increase or something like that. if i was you just get a 331, nice afr 185's and that systemax intake, custom cam, nice lifters, valve springs, ect, then 36lb injectors, and big tb's and MAF, and good exhaust and you should be about right.

 

[Marz]

ive done some looking into high hp small block NA motors, you can get over 350 with a 306 or 302(same thing), you have to have a good set of heads, and nice intake mani, and custom cam. compression at 10 is probably good, but i think i read somewhere that another 1:1 (ie 10.1:1 to 11.1:1) is about 30 hp increase or something like that. if i was you just get a 331, nice afr 185's and that systemax intake, custom cam, nice lifters, valve springs, ect, then 36lb injectors, and big tb's and MAF, and good exhaust and you should be about right.

That same combo was close to what I had in mind. I am thinking 10.25:1 comp. with 14 degrees of timeing and on race day boost it to 16 with 100 oct.
Those AFR's flow really good so to make it a little interesting I was thinking of fully porting the Holley Intake. Custom Cam is a definate.

Would a 75mm TB be to much?

 

[25thmustang]

I think you need to research a little more. If you are already talking about what timing your going to run... you need to look into building a motor LONGG before you worry about timing. 10:1 306 will be very very tough to make streetable 375+ to the tire. Bigger cubes is easier to make more streetable power. A 347 stroker is a good start, but stock block or no? If you plan to spray a 375 rwhp motor with a 150+ shot, a stock block might not be smart. Heads are easy, cam is someone elses job (custom is the way to go) carb vs efi is a tough choice.

Do you want a 7000 RPM 306 that works great on the track and ehh on the street, or a 6000 RPM torque monster that is more suited for the street but probably more expensive.

 

[Mr. Rustypwnz]

im buying a 306 with 11 to1 comp and afr 185 heads and a custom cam here soon if my vert sells, and it runs 6.4's on a 150 shot, and about a 7.0 or so on motor, so yeah your gonna need some displacement to get to where your wanting, I dont know how much power it takes to get to a 7.0 in the 1/8th either, but dont sell yourself short and go with a 306 if you want high hp n/a.

 

[ryan218]

start with a 408....:d

 

[underdog225]

http://www.dndmotorsports.com/?page...category_id=6834dda8e3e6e5aa18bafc63a57fd04a&

 

[Mr. Rustypwnz]

well nm it seems Im buying a freak 306 that runs 10's on a 200 shot.

carry on!!

 

[grey5.0beast]

HCI 306 with a 200 shot should have no prob running tens noob

 

[92GreenGT]

Do you guys remember Jason Moore(NoSlo90) I believe was his screen name, go look up the combo of his 306 that was used in the muffler test. It made 374rwhp, cant get much closer to that. Here is the combo under the picture:
http://andersonfordmotorsport.com/media/rumble2.jpg

 

[Dmarstroker]

Theres a guy on the moddedmustangs forum who has a CHP 347 motor that puts down 416rwhp naturally aspirated. Here's a link to his proflie

http://www.moddedmustangs.com/forums/profile.php?mode=viewprofile&u=1713

 

[Marz]

I think you need to research a little more. If you are already talking about what timing your going to run... you need to look into building a motor LONGG before you worry about timing. 10:1 306 will be very very tough to make streetable 375+ to the tire. Bigger cubes is easier to make more streetable power. A 347 stroker is a good start, but stock block or no? If you plan to spray a 375 rwhp motor with a 150+ shot, a stock block might not be smart. Heads are easy, cam is someone elses job (custom is the way to go) carb vs efi is a tough choice.

Do you want a 7000 RPM 306 that works great on the track and ehh on the street, or a 6000 RPM torque monster that is more suited for the street but probably more expensive.

Thanx for your input. Well I was thinking of getting this built with a well preped race block or even a sportsman. Your right, the last thing I want is to get a close to my goal and then have a weak block split in half.
I will be going with a 6000RPM motor. I don't waant to spend and arm and leg but I don't plan on slacking off this project. This is the car I plan to keep.

 

[302RollinHard]

like I said before, 351 swap.....Stronger block, more cubes, only 50 or so more pounds on the nose, ability to stroke it out later....possibilities are endless.

 

[25thmustang]

I agree, for a street car maybe a 351 swap. Go carb if your not worried about emissions, some good heads, decent cam, carb, intake, full exhaust and getting 375 would be pretty easy. My dads looking for mid 400s and 500+ tq at the tires on his N/A 393 stroker. Granted it will be a race motor, but wont rev over 6500 RPM, and would probably make a great street motor, with less cam in it!