400hp is not very hard with a 350 at all - even 450 or 500 is doable with the right parts. I have a 400hp 350 in my Camaro right now - mild cam, heads, and ancillary parts will get you there.

What I'm going to suggest you do is build your 400hp 350 with everything minus the high rpm intake (cam, heads, exhaust, fuel) and run it for a while with your stockish TPI style intake. Then when you are ready, change the intake and get all the HP you left on the table with the long tube runner design.

I'm not a fan of supercharging, but keep this in mind: a 550hp NA 350 is going to be barely streetable. But a 400hp 350 with a 150hp nitrous kit will work well on the street and the track with pretty darn good manners.

that EXACTLY what i want to do. i dont know what spec products will get me in that range, the intake is simple and is the last thing i will do. the heads and cam are difficult as i dont know what im looking for.

I've heard guys having good success with something in the spec range of the LT4 hot cam. That may be a good option for you

comp recommended

part number 08-503-8
grind XR276HR
224/230 .503/.510 112*
http://www.compcams.com/Company/CC/c...?csid=196&sb=2

with 180cc/64cc heads
http://www.racingheadservice.com/rhs...nder-headhtml/

any opinions on this? this seems like a pretty decent recommendation from the research i have done

What size are your combustion chambers stock? I don't think you'll be near your 450hp, or even 400, but I think it will be fun on the street so long as you have the heads milled so that the scr, dcr, and quench are in check. This is me assuming 64cc is wayyy too big.

64cc came factory on iron head L98

Well you are going to want to get them milled down some to bump up the compression. How much? I have no idea, I barely know lt1s. Head gasket choice is going to matter as well to obtain proper quench. You'll need to know how far down the pistons sit. You should check out static compression ratio and dynamic compression ratio calculators. You'll have to find out what the l98's like though. Most lt1 guys run anywhere from 11.5-12.5:1 static pending the cam and 9:1 dynamic but we are a completely different monster with reverse cooling etc. I may be wrong in my assumptions here but I feel most will say get the compression up while maintaining proper quench. Guys will go anywhere from .035 to .050 but you have to be pretty careful with your measurements and rpm range with a tight quench.

And I don't think the parts are a bad choice, I think it should have good torque. I'm just not very familiar with your platform so take it lightly.

I'd go with these... http://www.racingheadservice.com/rhs...nder-headhtml/

1 point of compression is worth 4% more power (if the gas will support it), about 15hp on a 400hp motor. So don't worry about that - as long as it is around 9:1, you will be fine. You can always add some timing. You can also use a thinner gasket.

Need to be careful with the thinner gasket, as you really don't want to drop the clearance from the piston to the head under .035". Need to check if the piston is down in the hole or out of the hole.

stock comp is 9.3:1, L98 vettes run 10:1 with a smaller combustion chambers (58cc I believe). I may be able to get to 9.8:1 with the thinner gasket, past that I think there will be clearance issues.

Its not just static though and you should really measure the piston height, never assume. You don't just want to slap a thinner gasket in there as quench matters. That is why I suggested milling the heads.

That's a good combo. Also a popular one. After you do the manifold you might be able to get the power numbers you seek. You could back down the CC size to gain a little compression but I don't think it will matter much. I would do the 64cc and I think you will be very close to what you want. Until you switch to the short runner manifold the thing will be a tq monster for sure.

Why the low compression?

I run 11.25:1 on 93 with 36d of total timing.. So far so go. Then again, I have pretty decently ported 56cc AFR 195's

What kinda dyno numbers did you make? I know your car runs well at the track.

According to the dyno 4 years ago. 385hp/335tq. Then again I started the runs at 3800-6300 rpm and was out of injector. Since that I added the 42lb'ers and tuned the rest at the track.

So safe to say your build is pretty inline with what the OP wants, correct?

Yeah I would say shooting for something along the lines of Kat's build will get you there. But we are talking 355. How much would a 350 make with the same mods? Well it will be close for sure but will be less. This has all been debated to the end of the world and back a million times for 28 years when tpi first came out.

I know of a build with a TPI 350 where the guy is making 420+ but that is at the flywheel I believe. Even he admitted there really wasn't much more in it staying NA. At least in 350 form. Was using AFR 195s, and a TPIS Mini Ram intake. Sweet motor combination, but biggest flaw was tuning it with an OBDI computer. Best bet would be a megasquirt.

I looked into it, trying for 450-500 at the crank....decided with the money involved to do an about face on using the Gen one in a street car.

Uh I use the 730 ECM so yeah. Even with using the 385 on the dyno and 20 % loss through the drivetrain that makes it 485 or so crank hp.

This is why TGO can be misleading at times

Also I drive the vert everywhere. To dinner, track and back, drove it to floriduh and back. So why is using a gen I block wrong? ;)

Tho when I built my engine I just got done spending the cash on heads and intake when the bearings let go..... I would have done an LS instead haha

Bad choice or words, I admit, nothing wrong with using a Gen one in a street car. Hell I'm doing so now. LOL. Just saying with 350 cubes and a TPI intake...not really much can do to get past 500 at the crank, let alone the wheels. I agree TGO can be misleading, I just was offered a deal on a LSX motor that I honestly would have been stupid to say no to. If the OP wants to play with a gen one, by all means do so. Nothing wrong with the choice, its the intake and cubes that can be limiting in his goal though.

Granted Gen 1 is not entirely a Gen 2, but they are certainly not close to LSX stuff.

So, +500rwhp is not doable by either?

Not when you top it off with tpi.

I agree with him here, stock TPI won't do it.

Easier with forced induction too...