budget build questions for the advanced tuners 6825 ecm $0d bin

Ok, I know I am going to catch a lot of flack for this, but the budget is really tight right now. I have a low milage 283 that I can replace the cam in (the current cam is waaay to large) bolt on my rebuilt 193 heads (I hand lapped the valves) and drop it in my truck for around $200. My questions center around 2 things;

1. if I am using the 8625 ecm, should I use the 350 knock sensor or will the 305 knock sensor work better?

2. In the bin, I have changed the displacement to reflect the correct value, and I will be using the 61# 350 injectors (I estimate HP at around 289hp at 5000 rpm) do I need to change anything else in the bin? I know that the fuel and timing will need to be changed to get it right, just need it up and running soon, I can make data logs and change my tables once it is running.

<edit> I realized my title got the ecm incorrect, it is an 8625 that I have a $0d bin in.

283 was a nice engine and very fuel efficient although it doesn't produce a ton of torque.

Knock sensor should match bore diameter as close as possible. A 3.8 / 3800 Buick engine is probably closest at 3.800" bore. If I had to pick a smallblock sensor I would use the 350 version.

Cranking fueling and acceleration tables are often MS pulse width and are not affected by injector constant. They could be very rich for your engine. Maybe someone who knows this mask better could address that?

The 8625 PCM requires using a 4K resistance Knock Sensor. I agree with 1project2many, a knock sensor with a near identical bore, as long as the knock sensor measures 4K +/- a very small %.

dave w

Thanks guys, that's the response I was hoping for. The block has been bored 30 over so the bore is 3.9, half way between the 3.8 and 5.7 bores.
I think the $0D mask uses injector sizing. I know the fuel will be way off, and I am fairly certain the timing will also need work, but that is okay, it isn't my daily driver.

Any thoughts on using a comp cams 12-230-2 cam. 250/260 adv. duration. 110 lsa. 432/444 lift with 1.5s, 461/474 in 1.6s. Will it be able to run at all on a stock $0D bin?

Comp's online cam selector doesn't show this cam for an EFI application but I think you'll be ok. It looks fairly mild. It's got less lift and duration than the Speed Pro cam in my '57 although the lobes are a little tighter. 35 deg overlap vs 64 on the Speed Pro.

Is this something you have already, or is one for sale at a good price?

Edit: I just started looking at cams for SBC and nearly fell off my chair! $250 for flat tappet cams??? Ouch!!

It's not an efi application cam, that is why I asked. It is fairly mild, with the 1.6 rockers I am at the limits of lift for the heads. I really can't afford to do to much work at the machine shop, so I limited myself to that cam. I found it at AutoZone for a really good price, but I am waiting until the first of the month to buy it. I have run a bunch of cams through Desktop dyno, and this cam seems like it produces the best numbers for the money I can afford. I am willing to look at other cams, but none of them seem to be very effective with this small a displacement and the 193 heads. I also try to get my torque in as early as possible, so a bigger overlap and looser lobs doesn't seem to work as well for a pickup.

I have a 350 hp 327 copy cam in my truck and that's definitely not an EFI cam. It wasn't as easy to use with the original 1983 Camaro ecm but the 7427 was easy to tune. I wonder if the EFI friendly qualities that were developed in the '80s when no one had access to tuning are still being applied to some of the cams.

Crane makes a couple of low rpm peak cams as well. 114102 is 500 to 4000 rpm while 113971 is 800 - 4600 rpm. I've used the 114102 with excellent results under a carb in a 350 with swirl port heads. The truck had 2.73 axles and a manual trans. The combination was very strong on the highway.
http://www.cranecams.com/uploads/cat...%20Catalog.pdf

Quote:

---

Originally Posted by 1project2many

I have a 350 hp 327 copy cam in my truck and that's definitely not an EFI cam. It wasn't as easy to use with the original 1983 Camaro ecm but the 7427 was easy to tune. I wonder if the EFI friendly qualities that were developed in the '80s when no one had access to tuning are still being applied to some of the cams.

Crane makes a couple of low rpm peak cams as well. 114102 is 500 to 4000 rpm while 113971 is 800 - 4600 rpm. I've used the 114102 with excellent results under a carb in a 350 with swirl port heads. The truck had 2.73 axles and a manual trans. The combination was very strong on the highway.
http://www.cranecams.com/uploads/cat...%20Catalog.pdf

---

I have run the Stock 305 HO grind in several TBI and TPI setups. Has a smooth idle with plenty of vacuum and makes good mid-top range TQ and HP.

Its like 202/207@ .050, .415/.430" lift cut on a 114° LSA and 114° ICL.

I have also used several of the 204/214 @ .050 grinds in them. With .423/.446" lift it would be a stretch to run a 1.6:1 rocker with stock TBI springs. Woth its 112° LSA and 4° built-in advamce it builds more low RPM torque but falls off on the top end more quickly.

I am a little off on the lift of the HO cam. The specs I have are for the roller version used in the 87+ LB9/L98/9C1 engines.

https://m.summitracing.com/parts/mel-ccs-37

https://m.summitracing.com/parts/mel-cl-mtc-1

That second melling cam makes a lot of ponies on small displacement. I wish the torque was stronger. I really appreciate the responses. I have checked out about 10 cams so far, all of which are not bad cams, but for the $ i have to spend, the comp cam still looks good for what I want. I need to go buy a set of small bore split ball gauges and measure my valve guides, I think I may have to spring for some more machine work. All of the valve stems I have measured (both intake and exhaust from 2 different 350's) are .334-.335 diameter, which is smaller than what I thought they were supposed to be, but having identical sizes between the two heads from different motors makes me wonder if the stock valves were just that size. I have 1 head in the shop right now getting surfaced, it was a little low between the 2 middle cylinders. My son and I took the 882 heads off the 283 Sunday, and the motor looks clean, still has some of the cross-hatch from when it was built. Going to redo the front and rear main seals, and maybe peek at a bearing before I start putting it back together.

Just go turbo. Even a mild cam makes power with forced induction.:laugh:

Back in the late 80's I helped build a budget / non-fuel injected 283. For heads, we used early 80's 305 heads with 1.84" intake and 1.50" exhaust valves. The 283 had 1.72" intake valves and 1.50" exhaust valves. The 305 heads were ready for unleaded fuel, which saved money not having to install harden exhaust valve seats into the 283 heads. The early 80's 305 heads with 1.84" intake valves had a similar combustion chamber cc size similar to the original 283 heads (about 58cc's if I'm remembering correctly). We used the factory 4 barrel intake and quadrajet carburetor from the early 80's 305. The camshaft was a re-ground "Clone" of the Competition Cam 252 torque cam of the late 80's. We also upgraded the ignition system to the early 80's 305 4 Pin HEI distributor. The overall outcome was surprisingly good, the 305 modernized 283 able to hold it's own up against an Impala 327 of the mid 1960's.

dave w

That's nice to know, I am only building this to last until I can get back in the black. Starting next month, I will have more work and that should ease the budget somewhat. Fixing my wife's Blazer last summer and fall kind of wiped out my budget for fixing my truck, so this is just stop gap. I bought a set of small bore gauges tonight, so I can check the guides. I hope that I don't have to spring for too much work on the heads, it will delay getting it back together. Oh well, so goes life in the country.

Well, I just can't seem to win. Took the better of the 2 193 heads in to get milled. Turns out it is cracked, no wonder the truck ran crappy. Now I just went over budget again. Do I just put the good set of low compression 882 heads on that I already own, and find an intake manifold? How hard is it to slot the center bolt holes on the stock tbi manifold to use the 882 heads? I will disassemble the 882 heads, and put new valve seals on, hand lap the valves and call it good. Will the 882 heads allow the .474 exhaust lift?

I'm thinking a 283 with 882 heads (about 76cc if I'm remembering correctly) will have a compression ratio that will be to low.

dave w

I agree with Dave. The 882 heads will make it tough to get the compression ratio you want. It's not too hard to slot the center bolts in the manifold but it doesn't look pretty afterward. What about buying a used set of heads? www.car-part.com?

I might pick up a head from the machine shop, or try to find a set of 58cc center bolt 305 heads, but the 882 heads are already paid for. Yes the compression ratio is low. I used my dcr calculator to get 7.9:1. I wish I could just afford new heads, but that money thing is a problem. I will probably bite the bullet and get another 193 head, then pay to complete the head I have.

Well thinking about the 305 heads, but 9.7:1 seems a ltitle high. So I guess I will wait and get another 193 head.

7.9 is low and you're dealing with an old chamber design so fuel economy might be low. It would run but I'd keep an eye out for a smaller chamber version. Maybe someone has reasonably priced set near you?

https://klamath.craigslist.org/pts/6052760055.html

https://medford.craigslist.org/pts/6060150751.html

https://medford.craigslist.org/pts/6044010787.html

https://medford.craigslist.org/pts/6041504992.html

Thanks 1project, I hadn't gotten to looking at craigslist yet. I may go look at the set in Klamath Falls tomorrow if the machine shop doesn't have something interesting. I know the 882 heads aren't the greatest, but they were on that 283 in my son's Nova, and it ran pretty good, just the cam was too much for how it was geared. I have pretty much talked myself out of using them, so that means finding something else. a set of 350 vortec heads? I think they were 64cc combustion chambers also. A few more ponies, and torque. Maybe I can find a set that isn't trashed.

<edit>

Well, 4 hp and 5 lbs of torque may not pencil out as a good bang for the buck with having to buy an manifold as well. I spend too much time doing cost analysis.

That's not much gain. You might see greater fuel economy with the new heads but it's hard to predict that. Ultimately if putting the engine together with parts you have gets the truck on the road and helps you get in a better place later, that's probably the best way to go.

I found a set of 191 heads that are rebuildable, not much more then new springs, seals, 50 up locks and hand lapping. $150.00

I'd give a set of L30 305 heads a try, they have a 58cc chamber IIRC.

L31 is rated at 255hp@4600rpm/330lb/ft torque@2800rpm
L30 is rated at 230hp@4600rpm/285lb/ft torque@2800rpm

Both engines use the same 191º/196º 0.412"/0.428" 111º LSA roller cam
The L30 305 is hampered with the single cat exhaust, while the L31 350 gets the better dual cat exhaust
Both engines use the same air intake, MAF, t-body, intake, injectors, manifolds, fuel pump FPR etc.

The L30 is only 25hp/45lb/ft torque down on the larger by 45cid 350.

the L30 heads can be had for much less than the 350 heads as well, look for numbers '520 and 059 for the 305 L30 heads.

But yes, you require the Vortec intake manifold.

peace
Hog

Quote:

---

I'd give a set of L30 305 heads a try, they have a 58cc chamber IIRC.

---

I was very disappointed when I learned the L30 head did not receive the same development work as the L31 version. The L30 head is similar to the previous L03 other than the 8 bolt intake pattern and lack of exhaust crossover passage.

L30:
http://www.crankshaftcoalition.com/w...BER_CN_059.jpg

L03
https://www.thirdgen.org/forums/atta...heads_0100.jpg

I've been wondering about the intake valve clearances vs. bore diameter with the 283. Is it possible the 1.94 intake valve will interfere with the 3.875" bore diameter of the 283? I seem to remember when I used a set of 305 heads with the 1.84" intake valves on a 283, there was just barely enough cylinder wall to intake valve clearance to be on the safe side for a mild performance 0.460" lift camshaft.

dave w

Good catch dave, I will double check. The 882 heads cleared, but have a really large combustion chamber. Hopefully the 191's will clear.

Quote:

---

Originally Posted by 1project2many

I was very disappointed when I learned the L30 head did not receive the same development work as the L31 version. The L30 head is similar to the previous L03 other than the 8 bolt intake pattern and lack of exhaust crossover passage.

L30:
http://www.crankshaftcoalition.com/w...BER_CN_059.jpg

L03
https://www.thirdgen.org/forums/atta...heads_0100.jpg

---

They have a very similar chamber to the 14022601 truck 305 HO heads. I had a 1983 G20 Van tha had thise heads. It ran very well with those 53cc heads. The 059s and 520s have a very abreviated swirl ramp and also do not require much timing to get good results. I think with the smaller bore they just did not require the chamber rework to get the results GM wanted. They still flow mid 220s on the intake port and have the same exhaust flow as the L31. I have a 305 L30 with a Lunati 268 High Efficiency flat tappet cam in a 1999 Tahoe. The power it makes is on par with a stock LM7 5.3.

Quote:

---

Originally Posted by dave w

I've been wondering about the intake valve clearances vs. bore diameter with the 283. Is it possible the 1.94 intake valve will interfere with the 3.875" bore diameter of the 283? I seem to remember when I used a set of 305 heads with the 1.84" intake valves on a 283, there was just barely enough cylinder wall to intake valve clearance to be on the safe side for a mild performance 0.460" lift camshaft.

dave w

---

That is interesting....I have run 1.94/1.60s on a .030" over 305 which is a 3.765" bore and it had plenty of clearance. 059 heads BTW. At .600" lift it had more than .100" valve to bore clearance. Offset dowls could have even increased that.

This is a 1.94/1.50 valve on a stock 3.735" bore 305 block at .0600" lift. Tested without a head gasket. A 2.02" valve would hit as soon as it came out of the chamber...About .0420"

http://i243.photobucket.com/albums/f...um/305bore.jpg

Good to know. I am concerned that 53cc combustion chambers with the flattop pistons will put me up over 10:1 compression, not exactly sure I could tune it properly. The 191 heads will yield 9:1, something that seems safer on an older motor with miles on it.

Quote:

---

Originally Posted by jim_in_dorris

Good to know. I am concerned that 53cc combustion chambers with the flattop pistons will put me up over 10:1 compression, not exactly sure I could tune it properly. The 191 heads will yield 9:1, something that seems safer on an older motor with miles on it.

---

I bet if you put the numbers down correctly it would only be 9.5:1 with the 53cc heads. My 1983 305 was about 10.2:1 from the factory. Flat top pistons with 6cc worth of valve reliefs, .025" down the bore, .020" thick steel shim head gasket and the 53cc heads. Pulled a couple of 85-86 305s with the same heads that had dished pistons in them.

Fast, thanks. I ran the numbers, and get 9.6:1 for 53 cc heads, certainly in the do-able range, I just can't find an affordable set of 305 heads locally that aren't trashed. A set of 305 centerbolt heads would be ideal, but almost every vehicle in the junkyard has got a ton of miles, and I don't need to buy more cracked heads. in the last 2 years, 1 head out of 8 was not cracked. I would buy new ones, and will later this year, but right now I just need to get my truck running. I like your results, and will look at the lunati cam to see how it performs with the setup I think I will be going with for now.

Update time--- I have the block cleaned up ( lots of elbow grease), the bores honed, the cam in, and the crank with the mains in. Putting the rings on the pistons, so in a couple of days if all goes well, the bottom end will be ready to button up. Then on to the heads. The 191s were really caked up, but the spark plug in the heads were the wrong plugs. They didn't even make it all the way in the holes they were so short. I got a 10 gallon bucket, filled it with degreaser, and boiled the first head in it for about an hour. What a difference. Still had to clean the exhaust side of really hard carbon deposits, but it sure is nice to have it clean. A valve job, some z28 springs with 50 up locks and they will go on the short block.