I just got done swapping a 350 into an 85 F41, i ran 16.9 with the 305, I'm running 15.5 with the 350, what in the hell am i doing wrong?
the 350 is running the following:
-355 4bolt
-profiled 5.7 rods
-flat top TRW hyperutectic pistons
-speedpro rings
-crank turned 10/10
-balanced rotating assembly
-PJ quiet gear drive
-comp cams XE-268H
-comp cams matched lifters
-LT-1 (64cc) 2.02's from a mercury marine racing engine, stock except for intake port matching
-stamped roller tip rockers
-stock pushrods
-edelbrock performer intake
-650cfm edelbrock 4bbl
-accel billet distributor
-8.8mm accel wires
-accel 45000v coil
-AC rapidfire plugs
-Flowtech shorty headers
-3" single all the way back through a flowmaster 40 series deltaflow
-stock accessories

the rest of the car is largely unchanged, weight is at 2900 fully loaded w/me in it, energy suspension poly rear swaybar links, 10" drag radials, 4pt rollcage, stock 3.08 posi rear, stock 700r4 w/stage 2 B&M shift kit, d/s loop, no emissions equipment, timing is right where it should be, carb is adjusted, stock converter (no idea about stall speed...guessing 1200).
I was told this engine setup makes 330hp on DD2k, sure as hell doesn't feel like it. Is a higher stall needed? Is it possible my valves are too tight and some cylinders aren't getting compression? It raps out real slow and I feel i should be hitting 13's or so with this setup. Should i go to a 292H cam and a performer rpm air-gap? Is there something i'm overlooking? I'm driving myself nuts and broke here, i can't figure out why it's so slow, I'm getting annihilated by 4-bangers and imports, i'm in hell, i'm desperate...........please help.

 

I just want to empathize with you. As I am in the same boat. 15.49 with my mods.

 

What kind of heads are you running? Heads can make a huge difference with little or no other mods and a built engine may not see much gains without good flowing heads.

 

Don't get a bigger cam, it will probably hurt you more. What are your 60ft times, and whats your trap speed? I think you are in need of a higher stall torque converter, even though your car is so light. My engine makes 300hp but I have a stock stall and it's killing my 60fts. Still, car weighs 3700 with me in it and I'm doing 14.8@94mph. If you have an older 700with 27 spline, I have a 1600-1800rpm convertor with 10k on it if you are interested. But you can also get a 2200rpm stall from a v6 s10 if you have 30 spline. Whats your timing at? Can you post the rest of the stats on your time slip? I think you should ditch the drag tires and use regular radials to reduce rolling resistance until your car gets faster. If you have the regular performer intake you would get more power from a weiand stealth, or the more expensive RPM air gap. But with your setup as is you should definetly exceed 98mph trap speed. Let us know the cars charachteristics going down the track.

 

What rear end gears do you have? Do you have posi?
GEARS and Torque Converter! (Preferably 2000 stall)

 

My best run on my stock wheels in rear (14's) was:
R/T .622
330ft 6.886
1/8 10.35@70.52
1/4 15.87@89.28

I changed over to the slicks because of horrible slip, they're protrac 50's on 15" wheels, the tree was taken down at midnight, but i feel like i probably picked up some lost speed and probally crossed the traps at 90-95 in low 15's or high 14's. I was shifting at 5000 and launching at 1200.

As far as my trans goes, i thought it was the 700r4 from the car, but it had a reman sticker on it, so i'm lost as to what year it is or what the internals are.

I'm not sure of timing right now, I had a friend set it so i could get the carb adjusted, then it was off to the track, i've gotten a full exhaust since then, seems like it's even slower.

 

Like i said, i've got a stock 3.08 posi (limited slip, always posi though) 10 bolt rear, only thing that may be setting it apart is that the F41 package has 4 wheel disc. I'm not willing to go much more than 3.73 just because I'm 17 and I have to be able to drive this car and afford gas with an afterschool job. I'd really like to get to 13's or 12's before i put a bottle in the back...
thanks

 

I missed the lt-1 heads... you should be running way better! Keep us posted on the outcome of your problem!

 

Are those parts "out of the box" or did you dial in the distributor and carb. If you don't have experience doing it, you may want to take it to a shop that will dyno tune it for you. Desktop dyno don't account for a bad tune, like how much initial advance, mechanical advance, total advance, and at what RPM etc. The performer intake is probably a hinderance too, an RPM might work better.

 

And finally (sorry, i'm posting seperately) the heads are off a LT-1 Mercury Marine racing boat. I was told that they had less than 100hrs on them, they were free, and they were in excellent condition. They casting number (it escapes me at the moment) is the same as that of early 90's vettes, they're cast iron, 2.02's, stock valves, stock retainers, stock springs, arp bolts, felpro fiber faced (i think thats what they called it) head gasket, all i've done is matched them to the intake gaskets with my dremel, nothing outrageous, just tried to smooth up the ports to lessen turbulence.

 

i didn't do jack to the distributor, got it set so the car ran and idled, had the car running pretty rich when it was on open headers, got the exhaust put on and adjusted it down until there was no more white smoke comming out of the tailpipe (running very rich). I plan on taking it to a reputable mechanic to look at it and tune it, but i live in one of those places where the "racers" are highschool dropouts with 14 dead engines in the front yard and the only shops are dealerships that won't touch my car because of the lack of emissions equip and fuel injection. If you know anybody in east central illinois (between kankakee and champaign), let me know.

 

for $20 you can get a book called how to tune and modify chevy engines? something like that. I'll have to look when I get home. All you need is a distributor kit ( weights and springs), some rods for your carb, and the book and you'll be tuning your heart out in no time. Best of all, you'll be able to do it at the track and see results. Then you can start collecting engines for the front yard, and impress the ladies

 

vette heads were aluminum, sure you got the right ones? check to make sure you're timing advance is working and set it correctly, i like 16° base timing and you'll want 36-38° total (i think it should all be in by 3000rpm). Did you tune your carb after putting it on?

 

A lot of people like to get upset when people mention timing could be the problem on this board. But I would say if all you have done is adjust it so it idles right it probably ain't right. You need to get a light on that thing and make sure you are at least at 8 degrees adv. at idle with no vacuum to the distributor. Even if you where using a stock HEI and the out of the box carb I would think that combo could break into the 14s.

If nothing else you at least need a base to start at. And knowing what your distributor is set at is pretty important. I don't think finding a mechanic to do that is at all neccessary. Timing lights are inexpensive and easy to use.

And when you get a timing light on it and make sure your base timing is good rev it some and make sure it is advancing as the rpms go up.

 

Is the engine new? How many miles. When I rebuilt mine I was amazed how slow it was, now with about 500 miles, it is really starting to come around except for my crappy heads. If it is a fresh engine just keep tuning and it will get better.

 

the engine is brand new and has 120 miles on it. what all have you done to tune it?
thanks

 

It is as simple as this. with only 120 miles on the motor your rings are not seated in the bore yet. Break the motor in before you start racing it. Get the timming set for good idle and easy start up. Get the curve decent to about 32 deg. Break in the motor. I put a fresh 454 in my friends 2wd short bed pick up and he was so disapointed with it untill we started getting some milage on it and the rings took a seat now he grins form ear to ear as we smoke mustangs and such with an old work truck.

 

Instead of going to a dyno shop, get a wide band o2 kit and do it your self. Try for a 12.5-13.5 air fuel ratio at WOT. You can get a kit from edlebrock via summit for about 130$ or make your own. The edlebrock is not as good as the Wide Band since the WB o2 is much more accurate.

 

YOUR CAR SHOULD BE HAULIN A#S!!!
Hey man check this out. I 'm running almost an identical setup in my S10. my mods are at bottom. I only made one pass with my truck at the strip before I through a flywheel 30 yards from the finish line and I ran a 13.7 at 99 mph, with only 18 miles on engine and tranny. If timing is on and carb is tuned its got to be your torqconv. or rear gears.



355 2 bolt fully balanced, pock. ported 041's, flat tops, xtreme ener. 268, alum.roller rockers, weiand Xcell, holley 600.

Th 350, valve body mods, steel sprags and 3200 stall conv.
3.73 gear with.....get this....welded spider gears

 

Ya know, i was reading somewhere about torque converter probs. My car feels like it lunges and revs when i slow down....if my torque converter (something i know nothing about) isn't locking up, or is always locking up, or is cycling, would it hurt my 1/4 mile times? Would one of those b&m torque converter controlers fix that? and do i wanna run with it locked or unlocked?

My base timing looks fine, my compression tester is showing that my valves are all seated in the compression stroke and my rings aren't leaking. How many miles am i gonna have to put on it before it comes alive?

 

in my experiance motors seem to start comming in around five hundred miles or so. Cast iron rings will seat a lot quicker than chrome moly or other high performance materials. Try and put 100 miles on it in one trip at a time doing the following. Start car and let it warm for about 10 min, drive in grandpa mode for 20, put it on the highway for about 10, then find a hilly road and pull up some hills with a decent load on the engine. Start in second from about a 25 mph roll take it to about 4500 rpm shift third and stay in it till about 80. Pull up about 4 or 5 hills like that and go back to grandpa mode and start obver. That should be your routeen a 100 miles at a time for the first 500 miles. After 500 miles relash the valves, check the timming, fuel, plugs ect. After that you should start to see what the car is made of and after about 1500 miles you can start abusing it. This is how I have always done it but I am sure others have there ways.