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ok thanks ... i mean cam, cylinder head, valves ... i want to upgrade the engine without replacing it, in italy there are more restrictive rules ... thanks to all
You will need to be able to do all the below yourself. If you would need to pay someone, I agree with the above - Keep the hood closed and enjoy the car as it is.
Taking the ridges out of the stock runners.
Use a 1.5” sanding drum with assorted grit – Leave about 0.75-inch of the sanding disk hanging off the end.
Trace them out on the stock plenum and the stock runners. Cut out the plenum dividers and shape as below. Bevel the runner FLANGE as below. Lay the edges back as far as possible but ONLY the area of the thicker flange material/area – NOT into the runners – they are too thin to “port”
Leave the bottom flange of the runners alone - do not bevel or “port”
TPI Base – for the 305, just take out the lip or “bump” that’s right past the runner’s entrance/input of the base (see below), put a small bevel at the entrance, and smooth out the rough casting – no porting really needed for the 305 and stock heads.
Add an adjustable fuel pressure regulator – set pressure to 40lbs as a start. Check plugs (immediately after a WOT blast – preferably 1/8 mile or so). Adjust pressure up or down as needed.
Adjust the lifter preload on the stock cam – set at 1/4 turn past “0”.
Set base timing to 10-degrees and run premium fuel (something equivalent to US 92-93 Octane)
Do all this and see what it does for you. None of this really costs a lot of money and won’t need any reprogramming (no chip needed). It won't make a ton of power but you’ll notice a seat of the pants increase.
Next thing would be full exhaust. Rules and regulations would determine the way you would need to go. If you could do 1.625” long tube headers with a custom built 2.5” crossover and no catalytic converter into a single 3.5” pipe and muffler, that would give you room to grow if upping the power later. If never doing a larger engine, just put on a set of 1.625” shorty headers and change the muffler - the Ultra Flo Dynomax is the best stock replacement in my humble opinion. https://www.summitracing.com/parts/wlk-17577
Doing any more than this will require spending a good bit of money that I wouldn’t personally do on a 305. I would not do a cam swap, nor would I put heads on it. If the above doesn’t do it for you, swap in a larger engine. OR, sell the car and get a newer more powerful car – the overall money might be less.
There are pages, and pages, and pages, of "Free mods" along with the subjective results of doing those mods. This forum has been around for 20 years, and all of those 'free mods' give you exactly the bump in performance that you pay for. It's pretty much a placebo, but if you want to waste your time and hack the car, go ahead.
Depends on what you mean by "increase". What is the first step in a direction towards? A lot of power? or just some free hp.
Assuming you are starting off with low cost and low power I would recommend:
1. Tune Up
2. Custom Tune
3a. Nitrous- most HP, easiest install, least intrusive.
3b. Cam (if your LB9 has the stock peanut cam that will be a nice, cost effective add-on if you are doing it yourself)
Other than that, I wouldn't spend much more on an LB9.
While everything mentioned in this thread, on a 305 TPI is "bad" and should be changed....the exhaust is an abomination. The Manifolds are a joke. The Y pipe is a bad joke. 1 cat isn't enough. Every thing from the cat back is great for scrap value. How bad is it?:
I took an '83 CFI car (rated at 170 hp) and put on Edelbrock TES "headers"/Y pipe -themselves, not that great and 3" SLP cat back. I also did "free mods" to it and it ran 14.5 @95 mph in the 1/4 at Epping. Anyone know how much hp it takes to get an F-Bod down the track at 95 mph? It takes ~230hp. That means I picked up ~60hp from exhaust, timing, no fan, cowl open, 160 stat. The timing probably helped some, but the exhaust was where the vast majority of the gains were made.
Yes exhaust is terrible. I've seen engine dyno's of 215 HP LB9's that were 255 HP on the dyno with no accessories and long tube headers. Exhaust is easily worth about 30 HP in a stock vehicle. Tuning should be done for best performance of course.
....While out doing a stock Ford Mustang 5.0 in the process. Makes sense; the ford already comes with sort of headers, and a real, dual exhaust with dual cats and H-Pipe...so you you move it to an engine dyno w/real headers, you don't see the gains that you see in that same move, with the F-body engine.
Last edited by Tom 400 CFI; 04-27-2020 at 02:56 PM.
so tom how do you advise me to proceed? do I change manifolds and put a valve in the exhaust to not change the whole exhaust? could you give me part numbers of the modified manifold please? I am in Italy and here it is very difficult to find pieces ... I would not be wrong to order them ... thanks
I would change everything from the cylinder heads to the tail pipes and I would do that how ever I needed to, to meet the challenges of you location:
Emissions?
Shipping?
Cost?
No "valve" needed. I'm not sure what you mean by that. (?)
There are 104 options from SUMMIT RACING and I'm sure that they'd ship abroad. Also, the classifieds on these forums, other F-body forums and eBay.
so tom how do you advise me to proceed? do I change manifolds and put a valve in the exhaust to not change the whole exhaust? could you give me part numbers of the modified manifold please? I am in Italy and here it is very difficult to find pieces ... I would not be wrong to order them ... thanks
Here you go...click this link right HERE. All stainless, that system supported 350 NET hp in the SLP Firehawk.
04-18-2020, 04:24 PM
