70StingrayL46

Well, maybe I should have listened to the others on here who have been down this road before but I guess I just had to find out for myself. The consensus seems to run about 3 or 4 to 1 on this and other forums that it’s just a waste of time and money to try to build a 305. I wanted to make the most out of the original engine and only alter what was necessary to make the car a bit less anemic and a bit more fun to drive. I never expected to turn the car into a racecar but I was expecting for the car to be a second or two quicker then what it is according to my G-meter. What I have managed to do is lessen some of the cars better original qualities such as being a great highway car with decent gas mileage and have gotten back very little improved power and acceleration in return.
Maybe you guys can offer a few suggestions besides the obvious one of dropping a 350 or 383 in it which may very well happen next year anyway. What I’m working with is a fresh LG4 305 auto, Edelbrock performer intake and cam, Rhodes lifters, stock 416 heads and Q-jet, Headman shorty headers, Hypertech chip and a peg leg 3.42 rear gear. With this setup, even with the 305, I think I should be getting better times then high 17’s and can barely turn the tires from a standing start… Part of the problem with the poor times maybe that the 2/3 shift is happening at about 500 or 600 RPM higher then what it should be for the best acceleration. Can I adjust the shift point? Any other ideas?

300hpse

iTrader: (2)

Compression is a power killer on the lg4, it's like 8.6:1 and the heads are a pretty big bottleneck too. Id try finding a higher flow set with slightly smaller chambers, even some stock l69 heads would be a huge improvement. Remember that an l69 is an lg4 with a bigger cam (which you have), better heads and maybe different pistons (dont remember to be honost) and a carb tuned to match and those cars were mid 15 second cars.

91interceptorZ

iTrader: (3)

I H8 WWD

iTrader: (5)

I am going a different route than well 98% of the people on TGO. I plan to completely overhaul my car with engine last (besides bolt ons of course, intake, exhaust, intake manifold). I will be setting up my suspension first, every part, everything adjustable. Then move into the interior and body of the car. Make the interior comfortable not only for me but passengers (my car will always be street capable). 8 Point cage, sport reclining seats (Corbeau), fiberglass 2 piece dash and center console, tubbed rear. Fiberglass fenders, bumpers, GFX, and hatch. Percy Speedglass rear windshield and side windows (keeping front WS glass). Lowered 2" all around on Wilwood 4 piston brake kit and 18"x9" Centerline Matrix's (so they can be rotated )...you see where I'm going with this, replace the maintenance, then go performance. I want a reliable car first, fast car second, if it means having a 700hp capable block and 1.6g capable suspension only pushing 350 and 1g, thats fine by me, as long as it is reliable and capable of using all the power it has all the time.

-Take care, whatever you choose I hope you do for you, not for anyone else or because of everyone else.

70StingrayL46

I'm pretty sure 416's are the heads that came on the L69, not that any of the 305 heads were really any good. Still, the 416's were supposed to be the heads that would pass for OK. The only significant thing that I am missing from the L69 (besides the performance) is the slightly higher compression of the flat top pistons. As for buying better heads....I thought about it but if I spend a $1000 on a set of World Products 305 Torquer heads then I'm halfway to a new GM 350 290HP crate engine in the price of heads alone and that maybe just throwing more good money after bad. I've read other posts on here and elsewhere that others with setups similar to mine are easily deep into the 15's so where are those other 2 seconds? As I mentioned before one of those seconds might be in the 2/3 tranny shift point but even taking that into consideration I'm still a solid second off the mark where I think I should be.....

mnorton

Are you sure of this? I think it's 9.5:1

camaronewbie

The 416 heads are decent - but they need ported/polished and the chambers opened up some - add a LT1 or better cam, and you should be able to tune in some better power. You can do the porting/polishing on your own - it's easy, but takes a few days - get an electric die grinder, a few carbon cutters, and search on here for a thread about 416's by Sitting Bull. Your cost grinder and all would be about $200 including new gaskets (shop harborfreight.com for cheap grinder).

Otherwise, like you said - bolting on new heads is 1/2 way to a 350 or better. Heck, I only paid $600 for my 350 from a local guy, pan to carb - and it's nothing special, but way way way funner than the 305 ever was or could be (for me).

EvilCartman

iTrader: (1)

9.5:1 on an 86 305. My 82 305 was 8.6:1.

SMURFN' Z28

iTrader: (2)

Not all 305s are slow. Mine runs mid 14s with just bolt ons and a T5. Granted, it is an '85 TPI, so it has a better cam, and 9.5:1 compression, but 17s seems WAY slow.

I am guess you have some sort of missmatch? Did you say you have an edelbrock preformer intake and cam? What are the specs on that cam? My guess is it is too big for a basically stock lg4. That and I have heard nothing but bad things about off-the shelf chips such as hypertech.

I am assuming that this is an '86 LG4, so it is not a roller motor. Look at the comp XE 249 for computer controlled cars.

70StingrayL46

Maybe I should have specified 305 LG4 because really I'm just shooting for the kind of performance that yours started out from the factory with, but with an auto insted. It just doen't seem to be responding as I expected. It is a bit of an apples and oranges comparison, yours being one of the quickest 305 combinations (TPI/stick) from the factory and mine being one of the slowest (LG4/auto). I know I'd be around high 15's or low 16's if I had a T5 insted of the auto because, besides getting a better launch, as I mentioned before, my 2/3 shift at WOT is happening at too high of a RPM, slowing the times down. But even taking all of this into consideration this still seems slow... esp. with 3.42's. The Cam is an Edelbrock 2101:
Duration Advertised
278° Intake/288° ExhaustDuration @ .050''204° Intake/214° ExhaustLift @ Valve.420'' Intake/.442'' ExhaustLift @ Cam.280'' Intake/.295'' ExhaustLobe Separation Angle112°Intake Centerline107°


Compared to:
Extreme Energy 249H
Duration Advertised:249° Intake / 260° ExhaustDuration @ .050'' Lift:206° Intake / 212° ExhaustValve Lift w/1.5 Rockers:.434'' Intake / .444'' ExhaustLobe Separation Angle:112°

The 2101 cam may be a little on the big side, it has a little more duration but similar duration @ .050, lobe separation and lift at valve, but that is why I put the Rhodes lifters in which did seem to help the idle, vacuum, and low end torque.

Anyone have any idea's on how to adjust the shift points? Manual shifting doesn't help any because I'm not trying to get it stay in gear and shift at a higher RPM but at a lower one. All of my performance/fun cars in the past have been manuals so i'm a bit out of my element here.

gregsz-28

iTrader: (1)

17's is very slow. An LG4/auto car should do 16's stock. I don't want to waste my time taking my LG4/auto car to the track, but I believe it could do mid-high 14's. I believe the cam you have is too big, too much duration.
My modifications are longtubes, duals, removed emissions equipment, and 3.42 gears, plus a few suspension bolt-ons.
BTW, '85 and later LG4's have 9.5:1 CR, and they have the same heads as the L69. '85 and later LG4's and L69's have the same pistons. Don't forget that L69's have better manifolds and air cleaner assembly.

70StingrayL46

Sorry, but that is something that I would have to see to believe because IMHO there is no way that an otherwise stock LG4 auto with gears, headers and emissions removed is going to break into the 14's. Many people who do take the time to take their cars to the track are surprised the first time out with them. Stock F-Bodies with an LG4 and auto were 17 to 18 second cars when new. I actually drove my car in 87' when it was only a year old and have owned it since 94'. It was completly stock untill recently. I do agree with you about the cam though... it probably is a little to big which is why I put the Rhodes lifters in and noticed an improvment right off. As I said before, if I could figure out how to lower the 2/3 shift point my times would drop by about a second right off... Then maybe with an underdrive pulley, some roller tips and cold air induction I could get into the high 15's which is where I set my goal in the first place....

gregsz-28

iTrader: (1)

Yeah, I don't really know what it would do, that's just a guess, but I don't seem to have any trouble with cars that do low 15's. My car does seem to be lighter than average, IIRC when it had 100% of it's stock weight it was at 3260 lbs, now I have done a lot of weight reduction.
I'm almost sure I've read on TGO before that LG4 cars could do 16's.