Hello all-

I have a .030" over 350. It has cast four eyebrow flat tops, the deck clearance is .045", it uses 76cc 882 cast heads with .040" compressed thickness gaskets. I have calculated 8.3:1 or thereabouts.

Cam is a comp 268XE, .477/.480 lift, 224/230 @ .050". With a dual plane intake, reworked Q-jet, Mallory HEI and in a 3200lb S10 it did a best of 14.12@97mph at a track 600' above sea level on a 60* day. Truck has 3.73 gears, 700R4 with mild 12" 2200 stall converter.

I have a set of 081 casting 305TPI heads, 58cc chambers I am tossing on. GOt them used and cheap from a running engine. Did a suction cup lap on the valves and swapped my Comp springs retainers etc. on to them.

With the same type of .040" thick head gasket I figure 10.0:1.

Yeah I know it's going to rattle- but it's a short term see what it'll do thing. I know I went backwards from 1.94" intakes to 1.84's here.
I have not put the heads on yet, but they are ready to go on.

I think I will pick up torque but the 51-5200 redline will remain the same.

What do you all think?

Eric in Savannah

 

well not real sure about the 081 casting # heads, but as I understand it, the 882 heads are the worst going, due to, among other things, bad runner design......almost any head would be an improvement.......search some of the posts on this thread going way back, and you should find some good information.......

 

i think the 882's are better than 305 heads. 882's flow just over 200 stock. most duoble humps only flow about 210 stock. small valve, small runners. the only good thing is the small chamber. just put a smaller carb on it if you want to go slower. or get some darts with a 48cc chamber and 2.02 1.60's.

 

You're in the right place now.
You can port out the 081 heads and you'll really be having fun. Those 081's are very similar to 416 heads. Also you can port the chambers a bit to increase flow, and drop your CR level to where you won't be in ping territory all the time. See my sig for the VERY similar combo I run. (no track times yet).

oh right, you're the guy who quotes his weed whacker in his signature. haha, that's an unforgettable sig.

 

I JUST NOTICED TO!!!!

 

With the big jump in compression and nicer combustion chamber you should pick up some et. If you can maintain traction. At this point with the heads in as cast condition you probabily will not pick up but a few horses.
But now you have somethng to work with. These TPI heads have a ton of power potential that you can tap into.
They will need full porting and larger 1.94x 1.60" valves.
In full ported modded form I believe you should be able to knock off .700 to 1.00 sec from the et and pick up 50 60hp.
I'd be interested in how you make out at the drags with them installed as they are now..as a baseline.

At just a tad under 10:1 cr you will want to accurately set your ignition total timing. It will want 32 to 36 deg.
Get a advance timing light and verify your timing. Start at 32deg and see what the motor wants for timing.
I would install a spark plug that is cooler than "stock"
The "stock" plug is biased towards stop and go city driving to reduce fouling. (its hotter) A high compression motor that you'll be racing needs a cooler plug. This will give you some detonation resistance.
Use premimum 92-94 octane fuel. What ever gas is the best in your area.

 

If the specs you posted are accurate you'll go from 8.24:1 now to 9.83:1 with the smaller 58cc -081 heads.

You probably won't notice much difference on the top end, but torque everywhere below that point will be night-and-day stronger. Raising compression a point and a half will do that for you. And that cam will appreciate the compression being raised out of the toilet, too! Several good reasons why just raising the compression will really help out that combo.

Agreed, in stock form the 305 heads won't flow quite as well as the old 882s, but the compression ratio increase will more than make up for that. Don't expect to be able to run 87 octane any more, though!

And, by the way, the 2 center bolts on the -081 heads are "stood up" at a steeper angle (1987-up intake bolt patern) than your old 882s- modest intake manifold modification will be required.

 

I knew some of you guys would get back with me, and somehow even though I have not been here in a long time Damon, F-bird 88, Sonix and others have come through.

Yeah I know these heads "when ported" make power. But I am merely slapping them on, I am about 6-800 bucks away from completing another build (406) so I wanted to see what I can do with minimal dollars with what's under the bench.

I do appreciate the advice on the timing to start with. Traction has not been a problem so far, I have a bog with 2.00 range 60' and it dead hooks, converter is pretty tight. I think the low end tq may change that and it will be fun finding out.

I already have another Wieand intake like mine someone modded the center two holes for later heads too.

Thanks all!

 

damn straight, on my build i used some cleaned up 416s that put my compression just north of 10:1 (cant remember exactly now) and its fine on 91oct and has got alot of grunt down low. But i can tell the heads are choking it down quite a bit on the higher RPMS, but hey its all good for now, it can still bust both tires loose (open diff too) and smoke them right through 3rd gear for as long as you keep it to the floor (mile or so till it runs out of gas )

Its nice to have that bottom end grunt for in town though, its a night and day difference over my old 350. You just barely have to touch the gas and it pulls nice


Now when im rich and famous i will finish off the car...

 

Hey 84 Z that's just the kind of report I was hoping for- on antother note, did you get "Doo" any riding this winter? I picked up a '73 Olympique 340 sight unseen for $175 bucks off Ebay, flew home from Savannah GA to central MN to ride for the first time in 16 years! Ran fantastic, and the turned heads I got on the trails were great-"What year is that?"

 

Can anybody tell me if an AC R43TS is a good plug to use for this, and what gap to set it at? Igniton is an out of the box Mallory HEI.

 

.040" is a good place to start. yep, that plug should work I run the R42T. You may not want the "S", that means it's a projected tip. If it tends to ping more, go cooler and get a less projected tip like the R42.
Run it for a while and see what the heat line looks like on the plug.

 

Well I fired it up at about 1:30am last night, ran it in the garage a bit, I am going to readajust the valves today, heard a hissing on cranking so I mamy have an intake a wee bit tight. Otherwise it started right up.

I set the timing at 10* initial, but when warm it's hard to crank so I think I will drop it back to five degrees or so. The 76cc heads needed 10-12 on the street. I know this CR increase would require less lead and will need less total so I will have to play with it.

Will go get some R42T's today to replace the R43TS's that are in there.

The cranking CR with the old setup was 160 psi, I am going to check it with this setup. Definitely sounds different, starter is grunting more.

 

Good to hear you got it fired up!


Yes i did manage to put some miles on the sled and its still sledding season up here!

After a few minor setbacks (rebuilding motor then rebuilding complete sled after writing it off shortly after) i still managed to put on over 4000km this year

 

I put some 601 heads on my flat top 350 last summer. It had bigger valves and screw-in studs installed, but the ports and chambers were untouched. The power those heads made over the 882s I had on there before was unreal. I wouldn't be surprised to find out I gained 40ft-lbs at all RPMs below 5000 from the heads alone. The 601s are very similar to the 416/081 heads, they just have slightly different 53cc chambers instead of 58cc.

 

Okee dokee- well, the hissing was one plug I had in hand tight as I couldn't locate my cut down socket for header clearance at the time and knew I was changing them anyway. Store open on a Sunday did not have any R42T's but had the Autolite cross over, a 144, so I took 'em. Rechecked the valves, they were fine.

Had managed to melt the pickup on my dial back timing light against the header last night so I had to revert to my old non dial back one, set the initial to 8* with the vacuum unplugged to the disty.

Took it on about a 20 mile loop- first off, it had some 89 octane in it that was a month and a half old, and I could not hear a hint of detonation taking it up a bridge grade (only thing we have for hills here in the coastal plain) at 40mph in overdrive. I am using full manifold vacuum.

Pulls like a ****! Yes, feels much stronger though I did expect a little more below 2000 than I got. Also pulls to about 5500 which I did not expect. When hot it still cranked hard, so I'll back the lead down to 5* and see how she is.

The bad? Well my trans now has decided it does not want to upshift 1-2 under WOT and it never did that to me before. I will recheck the TV cable adjustment, it does not matter if I am manually shifting (B&M megashifter) from 1-2 or stabbing it to the floor and leaving it in "D", it does the same thing, I hit 6200 and it cuts up and goes into valve float.

After I got home I realized I had not put the 2007 sticker on it (expired last February) nor my new insurance card. Not that getting sideways winding out first in an industrial park would have been reason to get pulled over had there been any law around mind you........