Biggab12

Hi there, i was looking to but some vortec head on my 305 with the tpi system. First of all, my car is all original, never modified, only trans coler and cat back. My question is: can i acheve 300 350 engine hp with the follow upgrade and can i programme my stock computer to go with those??

Upgrades list
1.Scoggin dickey (intake, modified vortec heads, runners and the header) https://sdparts.com/details/scoggin-...er/sd8060ratpi

1.2.Might reduce the chamber of the vortec head to 60cc to keep a decent compresion on a 305.

2. Xtreme energy 266HR-14 Cam http://www.atlanticspeed.com/product...idproduct=1325

3.Some South bay injector, something like 24 or ( 36 if i can use higher flow injector with a fuel real to equalize the mix, if im thinking about more power later ?? ex zz283 base or zz4385)

4. Already have a cat back manaflow, 3 in and out, no cat.

5. Bigger throtle body (52mm) and ported tpi runner

6. Installing a Egr out (like on corvette to stay emmision friendly)

7.Rear axel swap (2.73 to 3.42) with the special thicker gear for serie 2, 10 bolts.

The two main thing i am looking (exept more power...) is a good drivebility and a good idle. I will only use this car on the road as a second car.

Plz, i dont geave a f..... about guys with bigger engine is better (even if it true.....) im staying for now whit a 305 tpi

Thank a lot for any help or advices

darbysan

A couple of random thoughts, based on my experience. Change the rear axle ratio first. It will feel like you have a new engine. Changing to Vortec heads will give you a few more HP on the top end ( useful at the drags), but for a daily driver you want low end grunt ( torque) for those stop light dashes. Remember, torque gets you going, HP keeps you there. HP is only a derived calculation from torque.

An easy upgrade would be an LT1 cam swap. Still computer friendly, and will wake the 305 up quite a bit. For even more torque, you could use the B-body LT1 cam. It was designed for a little more torque due to the heavier body.

The Vortec heads are good no doubt. I have them. In retrospect, if I had taken the money I spent on Heads, Intakes, gaskets and EGR conversion, I could have easily had the stock heads ported to flow the same numbers as the Vortecs, and had a boat load of cash left over. By stock heads I'm talking the 081 heads ( not sure which ones you have- maybe the 093?). Even so, I feel like my old L69, with TPI, LT1 cam, headers and high flow cat, was pushing maybe 250-265 HP, and with the gear change, I could lite em up in 1st, 2nd and sometimes 3rd. I spent over $2500 for a crate L31 with Vortecs and a new intake to convert from my L69, and it certainly has more low end grunt, but I can't say I got my money's worth for the change. Many days I wish I had just kept the 305 ( and the money!). It was a sweet running engine.

Biggab12

I will swap gear first for sure, i know it make a lot in term of performance.

So if I got the good head (081) it's better to get those ported and put a lt1 cam in and some header? That way it will be computer friendly and i will have enough of #22 injector and a 350tpi programation ?

(lb9 rollercamblock with ported head =260 70hp, 350 360torque, and whit vortec maybe 300 320 and close to 400tq) If im about right, i understand ur point by keeping the stock head for the money)

Still have to change the intake manifold or not ? I know the stock fit but... (some say it the weak part or tpi system)

darbysan

Can't say for sure it would be better than Vortec, but certainly close, and a lot cheaper. I doubt you could see 300HP with a 305 and still be computer friendly and streetable. There is a slight improvement in flow with the TPI intake, but a lot of money for just a little improvement. If this was a drag car, where every HP mattered, then I would say your first build plans weren't bad, but for a daily driver, I don't think you will be able to tell much difference, except that your wallet will be lighter!

The 081 heads will fit your current intake. I have seen some reports on the net that the '87 LB9 had the 081 heads, so you may be OK to start. Don't think I would go to larger injectors, unless you also go with an adjustable FPR. 21 or 22 LBS is too much for a 305. If it were me, and I had the 081 heads, I would change the rear gears first. If you want more after that, swap in an LT1 cam. If still too slow, then consider the heads, etc.

I think you may find that the change in gears and the better cam will give you all you might want on the street, and then you can put the rest of your money towards your bigger engine ideas.

Biggab12

Thx, i will make the gear swap this summer and after that i will know if im ok with it or not.

so no need to but bigger injector even if a but a lt1 cam, i ported the head and put some header.

Sound a lot less expensive.

darbysan

You should be fine with stock level injectors. If yours are original, might be a good time to upgrade them to Bosch 19 Lb while everything is torn apart. With an Adjustable FPR, you can even use these to drive a mild 350 ( I am).

billyhoss

iTrader: (1)

I have pretty much did everything you wanted too do. if you have any questions pm me

rusty vango

congrats for not listining to the "threefiddy" crowd. im doing the same on a street driven lb9. but mine being a 86 ,im using fully ported "416" heads under a 87 roller block..with stock tpi manifolds. and i have a nice dd with good mpg to boot.what the 3fiddy crowd dont seem to understand is this; some of us dont give a f about burning as much gas as possible ,as soon as possible. we are going for mpg and decent streetable power.

86T/A_Ram_Air

I would use World tourqer 305 heads. They will definitely keep your compression up but pump gas friendly and are a good set of heads

Fast355

iTrader: (2)

I would get a set of ZZ4 heads, get the valves back cut if they are not already and run the hell out of it. The ZZ4 heads are lighter aluminum, have bigger 1.94 intake valves, flow better than any 58cc head other than the 059 vortecs and trickflows, and can often be had fairly cheap from ZZ4 owners that have upgraded.