13sec83trans

My plan with this car has always been i'd be happy when I'm running at least 12s but I'm not really sure the best way to go about it. I'm 24 and my engine knowledge is ok at best. It runs a 13.6 as it is now i don't want the car to be any faster than a 12 and id be happy with a 12.9. here is a list of things done.

1972 sbc 400 bored .30 over = 406
forged flat top pistons
485 lift 224 duration at 50 degrees camshaft
72 stock 400 heads
valve guides, seals, springs & 3 angle valve job
Edelbrock performer intake
750 edelbrock carb electric choke
HEI distributor
MSD 8.5mm wires

Th350 trans
B&M shift kit
deep pan govener recalibration kit
stock torque converter
ratchet shifter
Spohn performance steel drive shaft
Spohn performance trans cross member & torque arm

3.73 posi
Hooker headers & 3in exhaust
runs on 10w40 full synthetic zinc enhanced edelbrock #1072
Aluminum 3 core radiator
Hi flow water pump & hi flow 195 t-stat
E3 Spark Plugs ETP-E3-42

I look at this and i see heads but seems to expensive and maybe not that great of an increase. i thought about doing ignition box and replacing the GM HEI distributor so i can increase the gap on the plugs a good amount but that isn't much power. i don't want to do nitrous, turbo or supercharger. I have no hood clearance for a high rise intake.

What you guys think? seems the obvious answer is heads to me but let me know what you think i would greatly appreciate any help.

sofakingdom

iTrader: (1)

Heads, cam, block, carb, intake, trans, all wrong. ... yeah .6 sec sounds eeeeezy but with what you've got now, ... not so much.

You've got a typical crappy late 80s combo, that I've seen DOZENS if not HUNDREDS of people disappointed with. That's when I was building most of the motors that I built, and the horror stories are ALL alot like yours.

Vortec (96-2000 truck) heads (of course we didn't have those back then; our hot tip was 186s off of a station wagon or the like, not the right answer in 2017 though). LS6 valve springs or equivalent (PAC 1218), Comp 787 retainers, Manley Street-Flow valves, positive seals (NOT umbrella, NOT O-rings), light porting mostly just behind the valve WITHOUT removing very much metal and WITHOUT changing the port shape any more than necessary... no "port matching", no "push rod pinch", no "hog em out", just fix the multi various funky angle step abrupt crap from where the factory just kinda jammed the cutter in there, and some LIGHT smoothing around the valve guide to make it into an airfoil or "teardrop" shape... may require a small amount of machine work but the secret to effective use of those heads is to minimize the "professional" (i.e. YOU PAY FOR IT) hand work to them, i.e. DO IT YOURSELF.

Split-pattern cam such as XE274 (best cam I ever had in my 400 in my 83) or the Lunati Voodoo that's more or less equivalent

Performer RPM

Holley carb, preferably manual secondaries

3000 - 3300 RPM stall converter

Normal non-"gimmick" spark plugs... some one of the OEMs (Delco, Motorcraft, Champion, Bosch, Nippondenso, NGK, ... OEM, they're all good, the "gimmick" ones are NOT)

LCA relocation brackets

Curve kit for your HEI that gives about 36° "all in"; about 18° at idle; advance starts coming in just off idle, let's say 1200; "all in" at 2800 RPM or thereabouts (no stock HEI comes ANYWHERE CLOSE to that)

A 400 is BAD A$$. No better small block ever made. All ya gotta do is, make sure the air can FLOW through it. Heads, cam, exhaust, intake, ... not too complicated, think of it as like a big block using small block parts, and it makes instant sense.

13sec83trans

if i did get heads i was thinking the vortec heads but i wouldn't be able to port them myself or anything like that, kind of why i don't want to mess with them. you say valve springs, retainers and valves. would those help in performance or is that just for durability? sorry if that question is a noob one.
would getting the RPM performer intake be much of a difference over the performer i have?
the edelbrock carb i got has air valve secondary seems like a nice carb just got it recently to replace the quadrojet. edl-1411
i considered a stall as getting the launch would do best for my time was just concerned if street tires would handle it, dont really want to use slicks.
this curve kit is cheap i'll pick that up.
are the stats for my cam not good? or you think its a generic one that doesn't have the latest technology and geometry? i thought the 485 lift was decent but i really dont know much about that and you got 20k posts so i am inclined to believe you on that.

cardo0

Make it easy and buy a new ZL1 camaro.

86LG4Bird

iTrader: (1)

The one glaring item.....stock torque converter.

Replace that with a 3000 min stall 9.5" or 10" TC, and AT THE SAME TIME, mount sticky tires and LCA RB's, replace LCA bushings, and front torque arm mount/rubber.

Don't even think about going into the engine until that stuff is done. If it's tuned even close to correctly, it will be very close to 12's. THEN think about cyl heads and other engine work.

The cost effective way to ET's in any auto trans vehicle is torque converter and traction

sofakingdom

iTrader: (1)

The stock springs on Vortec heads are TERRIBLE. They're worse even than most other stock springs, NONE of which are suitable for ANY high-intensity aftermarket cam. They simply can't control the valve. No way you could change out the cam and make an improvement. In fact, even though you don't say what cam you have now, I'd be willing to bet that whatever springs you have, are inadequate for it, whatever it is.

Those old early 70s smogger heads are some of THE WORST for performance ever produced. Most of them were 624 or 882 casting. If that's what you've got, they are hopeless. I recall my GF in the late 70s (my wife now) complaining about her 74 Monte Carlo with a 400, and how weeeeeek it was; I went to the junkyard, got a pair of 186s, slapped em on there, and totally REVOLUTIONIZED the car. Improved both the compression and the flow in one blow. Probably a 15% increase in torque and 25% increase in HP, without changing the gas mileage. She was amazed at how such a simple, invisible, relatively cheeeeep thing, that the parts sitting side by side didn't look all that much different to the eye, could make such a GIGANTIC difference. You've got THE EXACT SAME situation.

But that was then, this is now. Those old heads are (a) no longer the "hot ticket", (b) are getting harder and harder to find all the time, and (c) even when you do, they're old and wore out. The best ones TODAY are the late 90s truck ones aka Vortec.

But, Vortec heads have an even greater obstacle to performance, which MUST be overcome somehow: their valve guides are YUUUUUUUJJJJJE. Using stock-style spring hardware, the retainer smacks into the top of the guide at around .480" of valve lift. One way or another, this HAS TO be overcome in order to be able to improve the springs. And it really needs to be done in some economical manner, otherwise the economic factor takes over, and it makes no sense to use those heads at all: might as well buy aftermarket instead of spending that kind of money working up stockers. The advantage of the heads goes away REAL QUICK when you have to spend as much on them to whip them into usable shape, as it would take to just buy BETTER ones from the get-go. Another issue with them is the diameter of the spring pocket: to get much past .500" of lift, springs with more than 1.25" OD are needed, but the pockets cant be enlarged without a significant risk of hitting water.

One way is the infamous "ghetto grind" aka Alex's Parts, where the bottom of the retainers are just ground down thinner. It works but not my preferred way of doing things. Another is to use .050" offset keepers to move the retainers up that much, then add .050" of shim under the spring to keep the installed height correct. But both of those fail to address the issue of the YUUUUUUJJJJJJE outer diameter of the guide, which prevents using a double spring, or even a single with a damper. And, by moving the retainer up higher, there's an increased risk of the rocker and retainer interfering with each other.

The LSx springs however, are a "beehive" design, and don't need a damper or an inner to do their job. They drop right over the guide. As-is, they are good for around .550" of lift, without having to machine on the heads. Then, their retainers are MUCH thinner, smaller, and lighter than stock SBC ones, which solves the clearance problem all by itself, while otherwise improving on the valve train stability. All you have to do, is use an "adapter" retainer with the SBC valve stem diameter (different from the LSx stem dia); specifically, the Comp 787. And as mentioned, just come very light port work; just enough to clean up all the weird angles and steps right behind the valves, from the factory just sort of jamming the cutter down in there and not smoothing it all out.

All around, the quickest, eeeezyest way to overcome the built-in limitations of the heads, economically; and thus allow use of a modern, high-intensity cam.

But as pointed out, often the best way to make a CAR faster is to work on THE CAR, not necessarily the ENGINE. I.e. do a better job of productively using whatever power you're already making. Even though your engine has ALOT of the classic smogger cripple factor built into it, there's almost certainly PLENTY of room for improvement in other areas of THE CAR, that you'd need EVEN WORSE if you ever fixed what ails the design of the engine. Converter (allow the engine to operate in the RPM range where it makes the most power instead of pinning it to idle speed), and TRACTION. Doesn't make much sense to talk about increasing power if the wheels are already just spinning or hopping instead of pushing the car.

bjankuski

A set of 195cc trick flow heads or similar will get you there. The worst part of your combination is the heads.

NoEmissions84TA

iTrader: (1)

Sofa, that was the most complete, most informative, and best answer to that type of question I ever read. I hope you have it saved so you can just copy & paste for future use.

sofakingdom

iTrader: (1)

Thank you. I hope it educated the OP.

13sec83trans

your post was very informative sofa. Sounds like i should save up for a set of decent heads then as i don't want to mess with stock vortec heads trying to get it right. Just a little intimidating to me. I will consider the converter i have some street slicks already chillin in a spare room. Whats with the LCA relocation?

sofakingdom

iTrader: (1)

Look at your rear LCAs. You'l find that the "frame" end is lower than the axle end. What that makes happen is, if you imagine applying a forward force on the axle, the axle wants to move UP... so if you apply a BIG forward force, the axle moves up (away from the pavement), the tires unload, traction goes away, the tires spin, the forward force goes away, the axle gets pushed back downward by the spring, the tires bite, the forward force returns, the axle moves up, the tires unload, .... all about 5 - 7 times a second. Aka, wheel hop. LCA reloc brackets lower the axle end of the LCA to where they're just about level, or possibly slightly lower at the axle end than the "frame" end (emphasis on slightly). Out of all the suspension mods I ever did to my car, that ONE THING made the biggest improvement in traction. Bigger than SFCs, bigger than an aftermarket torque arm, bigger than ... anything else. Lowering the car, or just sagging like they all do after 30 yrs, makes the original geometry which was already defective enough, even worse.

NoEmissions84TA

iTrader: (1)

LCA = Lower Control Arm
Another great explanation sofa.

bluegrassz

iTrader: (3)

Jegs makes a decent 10" torque converter for the TH350. I am running the 3500-3800 rpm version. I know it is not as good as some, but hey it works. The rest of my setup and times are in my sig.