nicole81

i'm the proud owner of an 81, with the stock 350. it's been nickle and diming me to death, but i don't mind, i love the car. i want to do some upgrades on the engine i just don't know where to start. any suggestions? :confused:

stickboy

One of the best places to start is with the exhaust. If you live in an area without emissions testing go with dual exhaust. If you have to get an emission inspection get a new cat at the very least. Going to a completely custon 2-1-2 system would be optimal tho. The stock cat has a single 2.5" inlet/outlet.


[Modified by stickboy, 1:06 AM 5/4/2004]

Dalannex

Exhaust is the most bang for the buck. True 2.5" duals with no cats and some high flow mufflers would be optimal depending on if you have emissions testing there or not. A cam swap to a Comp 260H or something similar is good, Edelbrock 3701 intake, Hypertech chip, A number of different high voltage ignition coils are available, headers, K&N air filter and filter top. These are all things that can be done without going through the engine completely. It all depends on how far you want to get into it and how much you want to spend. The things I listed above are all things that you can do one at a time, except that the cam and intake being done together would save doing the same thing twice in the intake install.


-Justin

BSeery

Depends on your budget, but here is what I would do in this order:

Exhaust, dual 2 1/2 and if possible headers.
Cam - 262 or 268 cam.
Heads - On the stock motor, a pair of L98 58CC heads really help compression. Not the greatest flow, but plenty for that cam and those pistons.
Suspension and brakes would be next.

UKPaul

A really simple, free, upgrade is to advance the initial timing from the stock 6btdc. After changing my cam & fitting a Hypertech chip it felt a bit flat just above idle. I advance initial timing to 11btdc & the pick-up was dramatically improved. I doubt if you'd see vast herds of horses released, but it improves driveability a lot. Not sure if you'd see that much improvement with a stock motor, but it's worth a try. I was told that it was safe to go to 13btdc but knocked it back a couple of degrees as fuel quality varies from place to place, some fuel causing pinging very easily.
See sig for mods. Swapping to MA 2 1/2" duals gave the biggest single power boost (even when running stock mufflers).
Justin & Bryan ( :seeya ), got any idea what vacuum those cams run at idle???
:cheers:

weendoggy

I know what you mean. Although I've been through every part of the car already. If you have e-testing (like we do in CA), you won't be able to do much to the stock engine or exhaust. A cam and heads as suggested (CARB apprvd.) and making sure your computer system works is about all you can do stock. If you want/need more, you'll need to upgrade to a newer engine and management system, i.e. TB or TPI. This will allow e-testing to the new year of the engine. If the newer engine had dual exhaust, then that would be allowed as well.

Dalannex

UKPaul, How's it been? I've been meaning to drop you an email to see what you're up to but as things go, i've been busy on the car projects and garage construction and haven't been on the internet much. :crazy: I went to change my ECM temperature sender last week after seeing that the to part of it was cracked and ready to fall off, so after carefully working the sensor back and forth the intake broke into large pieces all around where it screws into. :mad So, I ended up overnighting an Edelbrock Performer 3701 intake so that I could have it ready to go for our club cruise the next day. All in all it equalled an intake upgrade so that's cool. I also put a 180 degree thermostat in and installed a new electric fan switch that comes on at 200 deg. F. and off at 185 deg. Between all that I dropped my operating temp 50 degrees. :eek: Oh yeah, I also got the daytona II hood put on so the venting in the hood lettiing underhood heat out might help some too. I'll send some pics next time I clean it up. And the 200-4R is rebuilt and sitting in the shop but after looking at a local 81 with some fine transmission hardware from Keisler I am considering going to a trans where I can stir the gears a little. :cool: :D One or the other will go in this winter, for summer I'm leaving the 350C in there.

To answer your question I checked the vacuum the other day after installing the new intake and it runs 14 in hg. at idle, real nice and steady.


-Justin

Master Ho

Justin, with the mods you listed, do you have any dyno numbers or track times? Or an idea of approximate HP? I'll likely be following your lead this summer. BTW, if you decide to sell the 2004R, keep me in mind.

Dalannex

Sorry, I have no track times, dyno numbers, no nothing. The car hasn't been on a track (autocross, but not dragstrip) or on a dyno since I had it. I do go out every third weekend with a few guys, one is a 91 coupe, automatic and I can run every bit as fast as him. I don't have the top end since I run out of RPM's, but my car will pull just as strong. We had the 69' 390 HP 427 that I revived out with us last time and it pulls a little stronger than mine, not off of the line, but as we ran down the interstate at 75 side by side when we both stomped them to the floor the 69' would pull ahead. I have 2 complete 400 chevy engines in the shop and have been researching building up a 400 one way or the other or perhaps a 427 small block (although i don't know much about that one yet) and running the same carb and ignition setup as I am now (stock), only switching to headers from stock manifolds and playing with different jetting on the E4ME. I really want to put some big power out with the stock 81' ignition and fuel systems just to show that the E4ME isn't completely junk. :lol:

-Justin

UKPaul

Good man :thumbs:
Do you know anywhere that lists approx idle vaccum readings for cams? Most of the info I see is whether the idle is lopey or steady, which doesn't help us computer driven people decide on a cam!
Life is manic at the moment. Still trying to get a garage built for the Vette, but everything has snowballed (never thought Vette ownership would lead to a complete makeover for my backyard - there was me planning on happy evenings tinkering under the hood & I've ended up digging instead :lol: ).
Did you notice any difference after fitting the Edel manifold??? I fitted a 2101(? non EGR Performer), but did it at the same time as a few other things, so I'm not sure what difference it made). Happy building!

So's we don't completely hijack this post: if Officialdom prevents mods to the engine/exhaust you could approach it from a different angle. By boosting power all you're doing is increasing the power to weight ratio. The same can be done by lightening the car (which can get a bit extreme if you get carried away). If you can get by without the aircon then it's worth thinking about removing it. Mine didn't work so I pulled it all off. The box now in the attic weighs a surprising amount & the result is that the steering feels lighter. It's not a lot, but it's noticeable, the car just feels more nimble. I expect the acceleration is a tiny bit better due to less weight (not that I'd be able to notice) & fuel economy has probably improved. To try & keep weight distribution about right I then had to get some weight off the rear end. There's a couple of towing(?) brackets bolted under the rear impact bar that can come off (they don't weight much, but it's only a 5 min job to remove them) & I swapped the stock mufflers for a pair of Monza syle (like the KBD jobs). The weight of those stock mufflers is surprising when compared to the ones I replaced them with. Spare wheel can also go if you've got breakdown cover, but I'd leave the tub in place as it probably aids in the "aerodynamics" underneath.
:cheers:

Dalannex

Sorry, don't know of any vacuum at idle charts for cams, although that certainly would be helpful information. I like to think I gained some torque with the intake install, but I know that I did it too. Had somebody else put it on and not told me I probably wouldn't have even noticed, or maybe I would, who knows. You know, every time you put work into something you think you really made an improvement. Whether it's an improvement or perception, who knows. That's where I need that G-tech. :cool: It does seem like I have more torque, and like I don't have to step on it so hard during cruising now. I know for a fact my cooling system improvements worked, that one shows right on the temp gauge.


-Justin