I would like to eventually get my motor to the 300 horse mark, but what else should I do to it to get it there? It is a 305 TPI bored .030 over (dont know compression), a Comp Cams 260/260 adv. duration, .444/.444 lift, 112 LSA, Hooker 2460's and Hookey Y pipe, Flowmaster 80 series muffler, custom burned prom, K&N's, and a BBK AFPR. Other than buying a 350 to get to 300hp, what else should I do?

 

This is how I would do it:

- 416/601/081 cylinder heads, some port work if you're up to it, and screw-in rocker studs and guideplates, and have valve guides cut to handle about .600 valve lift.
- Comp ProMagnum roller rockers - these are the chromemoly ones that will basically last forever.
- Hooker 2055 headers and Y-pipe
- Hooker 3" catback
- Comp XFI268-HR13 roller cam
- GOOD cold air intake system.

Thats how I would do it, if I were starting from a stock 5.0 TPI.

 

It's got the 416's right now. Would a 305 be able to handle the lift that 1.6 roller rockers would give me plus what my cam has?

 

Displacement has nothing to do with how much valve lift an engine can handle, just what heads you are using, and if they are factory heads, if/how they were modified.

Most aftermarket heads will be capable of handling at least .550 valve lift out of the box, usually more. A stock LT1 head can handle about .580 as-is from GM. Vortecs are limitted to about .460-.480 lift. Most regular stock SBC heads are limitted to somewhere inbetween .470-.500 lift, including your 416s.
(** this is only clearance numbers, does not account for valve springs**)

But if you can remove your heads, its a fairly simple and inexpensive job to have a competent machine shop modify your valve guides to handle more valve lift, as they only need to be shaved down. You'll want about .30-.60 more "room" available than the advertised lift of whatever cam you are going to use, as just room for error. This would also be a good time to also have them pull out the pressed-in studs and install some screw-in rocker studs and guideplates (this requires some minor machining to do).

But lift alone is not as important to making power as is duration - the "duration @ .050" to be specific. 'Advertised duration' doesn't mean anything really. Duration numbers are what really defines a cam profile and what "separates the men from the boys" so to speak. Lift is only how far the valve is pushed open. Duration is how LONG the valve is held open, which has far more impact on power production and RPM range.

Example... two cams both with .450 valve lift. One has 210*/210* duration @ .050", one has 230*/230* @ .050"... the one with more duration is going to make a substantial amount more power and will pull harder at higher RPMs than the smaller 210* cam, because it will hold the valve open longer, allowing more air and fuel into the cylinders (assuming the rest of the engine combo is a match for the cam).

What cam specifically do you have? Whats the Comp P/N?

 

This is the cam that I have.
http://store.summitracing.com/partde...4&autoview=sku

 

this setup was good for close to 300hp in my friends LB9( camaro)

summit 1103 cam
heavily port/polished intake setup
113 corvette aluminum heads
shortie headers
matching y-pipe
full 3"catbcack
mild 700r4
3.23 gears.....car ran close to 13.7 all day(faster than stock lt1/auto 4th gen)

but the summit 1103 cam was almost to much cam for stock tpi

the summit cam is a flat tappet and 214/224 and .442/.465 with 112LSA

 

In your quest to get some power out of your 305 take the route of what has been tried to be successful. Here are some articles on what has to be done to reach your goals with a 305 build.

Hot Rod Magazine build produced 400HP. It has almost 11:1CR and peaks power at 7200RPM. Not exactly what you would call a Street motor.
http://www.hioutput.com/tech/400hp/400hp.html

PHR build produced 372HP @ 6,100 RPM 350TQ @4,500 RPM
http://www.popularhotrodding.com/eng...cks/index.html

Lunati build produced 343HP @ 6250RPM
http://www.goingfaster.com/spo/343hp305.html

Car Craft build produced 325HP @ 5500 RPM
http://www.goingfaster.com/spo/carcraft325hp305.html

RHS(Racing Head Service) build produced 290HP @ 5000RPM
http://www.goingfaster.com/spo/290hp305.html

Have fun and good luck as my 3rd gen came with a 305 and will keep it as long as I have it, but slightly modified for a good solid daily driver.