TVIROCZ

iTrader: (1)

Would it be worth it if I bought Edelbrock runners for a 305? I want to install shorty headers, I already have MSD ignition, MSD wire, E3 spark plugs, 3" flowmaster exhaust, Magnaflow high performance cat, Airfoil (if that makes difference) and K & N air filters. I reading on some boards that runners are not worth it for a 305 and more for a 350. If its not really worth it I dont want to waste money but I definitely want the headers. I am changing all the gaskets come winter. I am getting married so I don't want to go crazy now so I am trying to keep the car somewhat original. When the time is right I want a 350.

BlackenedBird

iTrader: (5)

Well.....The bigger runners will increase the rpm range some (move the powerband up) which is where smaller engines like the 305 are better at (than bigger engines with longer strokes) so I think it would help a 305 decently plus if you ever swapped out for a 350 they could be used on the 350 as well. So at least they wouldn't be like spending the $ on a chip for a 305 which would only be thrown away for a chip for a 350. So it wouldn't be a waste of money no when you upgraded later.

BlwnSS

leave the stockers there , trying to make the 305 tpi fast will cost money , save for headers and a cam .Gears would make the car better too .

ASE doc

Both Blackened bird and BlnSS make solid points. My first reaction to the question is no, don't bother with aftermarket runners on the 305. The factory intake will support 300+hp on the 305, 350HP on the 350. The key is heads, cam, and porting of the rough cast base runners and plenum. You would be investing some real time in porting the base and plenum, but all of the stock intake parts would be reused. You will of course need to retune the ECM for best results. Someone mentioned headers, which will help you get closer to the 325HP mark. That's a 100HP increase over stock without any expensive intake parts. As far as heads, consider the Vortecs as a great budget option. With some smoothing of the cast ports, they will certainly support 300HP. For a cam to work with the Vortecs, something in the neighborhood of 210-220 degrees at .050 and 480-500 gross lift. Don't go below 112 degrees LSA with TPI.

Other, higher dollar, head options would be the AFR 185s or as big as the 195s. The larger ports begin to sacrifice velocity for higher flow and since your 305 TPI is limited in flow anyway, the larger ports may be of limited value and may even cost you midrange torque compared to the 185s. However, the bigger ports will also support a slightly larger cam, more in the 220-225 neighborhood with as much as 520 lift(the AFRs generally support up to 600lift). With cleanup and a little small base circle smoothing of the exhaust ports, coupled with headers, you can even run a single pattern cam and pick up a little more intake duration to aid in cylinder filling.

Once you get to the top end of the head and cam spectrum, you may even get some benefit from higher flowing runners. Especially a siamesed setup like you can do with the SLPs. I personally run the TPIS large tube runners and have achieved pretty amazing results with them as part of a well planned and fortunate combination. To get the most out of the larger tube runners, you really want a ported hi flow base like the Superram or the Edelbrock. With an optimized cam and hi flowing heads, this combo would greatly increase your top end power and could get you in the neighborhood of 350HP.

BlackenedBird

iTrader: (5)

What about just having the stock runners Extrude Honed? Only $200 to do just the runners. Or $785 to do all 4 pieces (manifold, both runners & plenum). Keeps that stock appearance externally.

Tuned Performance

iTrader: (92)

you can remove the ridge in the runner and use a 1 1/2 steel ball to enlarge the tubes . not worth the money to extrude hone.

BlackenedBird

iTrader: (5)

What ridge & what is that about the 1.5" steel ball? Like pressing the ball through to stretch the runners? Never heard of any steel ball trick.

Tuned Performance

iTrader: (92)

the angle of the runner tube as it goes into the plenum and intake there is a lip left that needs to be ground down. This will expand the aluminum of the runners and remove the factory dimples in the tubes.
https://www.thirdgen.org/forums/afte...s-inc-tpi.html





http://www.ebay.com/itm/One-1-1-2-In...item460025615d

BlackenedBird

iTrader: (5)

Looks more like a way to remove dents which was not what I was asking about. I did see the line about the slight size increase, but that seems so minimal that it wouldn't be worth the effort of taking them off, buying the *****, doing the hammering then putting them back off. Minimal results for the effort required.

Nelz

No. The stock runners are are perfect for 305.

https://www.thirdgen.org/forums/tpi/...culations.html



See the above link.

ASE doc

Extrued honing is for cast pieces that have ample material in the walls to allow for enlarging. The OE runners are extruded tubing, about .065 thick, and do not allow for honing. Unless you think that paper thin runners are okay. I don't see where you can remove enough material to make any difference.

As far as stock appearance goes, the TPIS(AS&M) large tube runners are close enough to stock that the difference is very hard to make out. No one who is not very familiar with TPI would ever know the difference.