Rainmaster

The following refers to an LG4 in a 1985 Trans Am:

The cam swap has been done, and the results are in. With Comp's XE268H-10, Hooker 2055 headers/y-pipe, 3" catback, L69 dual snorkel, and non-cc q-jet with MSD ignition system, my LG4 was dyno tuned (adjustments to carb metering rods, jets, and timing set for max performance) and put out 185rwhp and 230rwtq. With an automatic transmission, I'm figuring that is about 230hp and 290tq at the flywheel. Does that sound about right? Also, are those good numbers to be putting out with my current setup?

As for the next step in my modifications, Heads seem to be the most obvious path to go down. After some research, I've come to the conclusion that Trick Flow's Super 23s should give a nice increase in power. Here is what I'm looking at: http://www.summitracing.com/parts/tf...0001/overview/

Do I have the right idea? I know a common suggestion is to port the 416 heads I have now, but I'd like to upgrade to aluminum heads and shed a little weight. I've read that the gains provided by head work/upgrades is usually dictated by how juiced up the engine already is. If that is the case, what would be a fair expectation to have in terms of power gains? A lot of times I see estimates ranging from 10hp-50hp thrown around on the forums. One last thing, I don't I've seen it mentioned anywhere, but would I see an increase in torque in addition to horsepower?

Thanks a bunch for all the help in advance! A lot of you guys on here have valuable words of advice and opinions which, as a young guy who is relatively new to this, are very useful to me (Off the top of my head, I'm talking about you SofaKingdom, Damon, five7kid.) so I appreciate your time.

86LG4Bird

iTrader: (1)

Unless you have a low mileage great condition shortblock there (and maybe you do since you've already decided it's worth a cam swap), I have a hard time encouraging you to go ahead with spending what will amount to about $1300 for installing those heads.
See my sig. I didn't spend one dollar on anything that was "305 specific". I put about $300 into a $100 Vortec core and gained an easy 100 horsepower.
Your dyno numbers look fair. Only about 20 hp more than I was getting out of the peanut cam with manifolds, not dyno tuned, just tweaked timing for best mph. L69 ECU/chip.

Rainmaster

The miles on my 305 are fairly low at 38000 which is why I put so much work into this engine. I know if I get the into engine swaps it won't be for a long long time, so for now I'd just like to do heads and maybe switch to an electric cooling fan and then call it a job well done on the power plant while I focus on other aspects of the car.

86LG4Bird

iTrader: (1)

Wow!....38k miles...I understand
Ok, I'll stop with the "swap it" talk


That's a lot of cam for a 305, so I'm guessing you could see about a 40 hp increase with the TF heads. I'd expect the peak torque number to be higher also (albeit at a higher rpm), since that cam isn't helping you at all where the stock heads want to make peak torque. I don't know how capable your stock? intake manifold is with a good H/C setup like that, so the more experienced ones here may want to adjust that 40 hp estimate.
I hope you're not staying with the stock torque converter for this. If so, the only place the car will shine is on the dyno rollers I wouldn't even consider any 12" TC for this. At MINIMUM, a 2800 9.5", and ideally something very high quality (great driveability) in the 3200-3600 range. And I'm not talking optimizing for dragstrip performance on slicks; for that, you'd need to go higher.
Don't be afraid of high stalls, as long as it's a quality TC. Something like a Yank SS3600 or PAS3400 drives better than the cheaper 3000 stall units, and certainly better than the crappy 12" converters.
How solid is the trans? I mention that because I believe the 1985 still had many of the 700R4 shortcomings that were corrected in later years. Not to burst your bubble; I would just keep some funds aside for that. Even the later ones don't take kindly to extra power and higher rpm shifts without shift kit/ valve body tweaks. And you'll certainly want to wind it high to get the benefit out of that cam!
I see you're in Phila.... when the time comes, there's a 700R/4L60 builder nearby in Delaware who some have had success with. There aren't very many 700R/4L60 builders in the country worth using; I happen to have an excellent one in Dayton, OH.


I'd be on the lookout for a steeper rearend gear; that powerband would really like 3.73's


Glad you mentioned the e-fan. My sig car already had that too, from the previous owner.

Rainmaster

Yes I forgot to add that I'd like to get a nice intake manifold to add to the heads. A torque converter is definitely next on the agenda after heads, though I may just swap to a T56 because I love manual and can only imagine how much fun this car would be with stick. Gears would probably occur at the same time as whatever I decide to do with the trans. The trans in my car feels pretty solid (also 38000 miles) and can chirp 2nd gear. If I stay with the 700r4, I will probably go 3.42 maybe 3.73, but if I go T56 I'm definitely going 3.73 possibly 4.10. I'm thinking the T56 would make this a really fun street car, I wouldn't have to do any shift kits, it essentially has a variable stall, and it would be funny to see how people react when I tell them it's a 305

86LG4Bird

iTrader: (1)

A T56 in there would be great! Not cheap and not easy, but when done, would be a fun ride.
I would go no less than 4.10 gears with it in that case. Gen 4 guys typically run 4.10's and 4.56's with the T56's .50 ratio 6th gear.

Rainmaster

That's what I was thinking. 4.10s would be a blast around town and I'd still have good highway mileage due to the T56's 5th and 6th gears.