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Discussion Starter · #1 ·
i have a 1989 chevy blazer with 7" lift on 38x15x15 wheels with 700r4 with 373 rear swap. 350 std. bore and stroke with .275 dome piston with estimated 11.88:1 compression. I am budget building and wondering what the best cam to use would be. I have stock 193 heads that i will be porting. preferably a torque engine. i was looking at comp cams xtreme 4x4 cam with, 262° Intake / 270° Exhaust, Duration @ .050'' Lift:218° Intake / 226° Exhaust, valve lift with 1.5 rockers .462'' Intake / .480'' Exhaust, and 111 lobe separation. i guess what my question is. can my heads except this amount of lift and is this a good cam for my application. i am hoping for a lope noticeable idol. Its a weekend worrier not a daily driver and only sees road between mud holes. Any and all help would be beneficial.
 

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The 193 is the dreaded swirl port TBI heads. These heads work great for low RPM power and torque, but due to the restrictive swirl vane they run out of breath at 4000 RPM. So just about any cam you pick will do no good past the point of 4000 RPM as the heads don't flow enough to support power past that point. I'd be looking into getting a set of heads before I worried with the cam.
 

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At 11.8:1 you're going to have to run race gas or E85. I hope you planed for that. Additionally, as noted the TBI heads are crap so you need a small cam to match them. the typical 204/214 "rv cam" is about right.
 

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Discussion Starter · #4 ·
Im allredy planing on race fuel and im not looking for high rpm. This truck is going to see very little highway if at all. It will be alot of big hills deep mud and river beds. So I want torque for the big tires plus i want the lopey idol. Not looking for crazy hp.. I bought a set of heads and they wer cracked and so im weary of huying heads or using junkyard heads.
 

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Discussion Starter · #5 ·
Im allredy planing on race fuel and im not looking for high rpm. This truck is going to see very little highway if at all. It will be alot of big hills deep mud and river beds. So I want torque for the big tires plus i want the lopey idol. Not looking for crazy hp.. I bought a set of heads and they wer cracked and so im weary of huying heads or using junkyard heads.
 

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Discussion Starter · #6 ·
Im allredy planing on race fuel and im not looking for high rpm. This truck is going to see very little highway if at all. It will be alot of big hills deep mud and river beds. So I want torque for the big tires plus i want the lopey idol. Not looking for crazy hp.. I bought a set of heads and they wer cracked and so im weary of huying heads or using junkyard heads.
 

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That cam will knock like crazy and make no power. You can not use that cam in 11.8:1 engine.

I use this to figure out my Dynamic compression ration then buy a cam big enough to avoid the knock. shoot for dcr of 8.5:1 then you can run pump gas.

Wallace Racing: Dynamic Compression Ratio Calculator

A bigger cam will lower compression until the engine comes up on the cam at higher rpm where the piston is moving faster and the fuel does not have time to heat up before the plug fires.
since you're running race fuel ignore this.



If you want good torque you need to forget about a really radical idle, they don't go together. A 274h06 cam is about the best compromise for most people. Run it with 1.6 rockers. You can find idle videos of it on youtube to give you an idea of the sound. It also has good torque from 3,000-5,000 rpm.
 

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Discussion Starter · #8 ·
Im looking at low rpm. Its not for racing. Its my play toy. I will compeat it here n there but just to prove street legal (ish) budget build can be just as good a crazy expensive built mud truck. I just have the biggest vehicle out of all my friends and I want to show them what my chevy can do. I will be changing the rears to bigger but im waiting till I am done so I can find best all around ratio. I am currently at a close stock ratio with the 3.73 rear swap. I will be going to bigger tires also after I run the tread off this set.
 

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Discussion Starter · #9 ·
I live in pennsylvania. Home of the harley. I can get 114 oc 5 miles from my house and there r 2 air ports near by. The pistons are reliefed for spark plugs allredy. Where else would I have to reliefe? I have a 203tc and its 1:1 and a 1.96:1 low. I wont go higher than a 5.13 rear
 

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Discussion Starter · #10 ·
Its weird down here with e85. There is a place a fuew miles from me but then its almost 60 miles till next one. Plus it will be to far between filling and I dont want to absorb water in which ethenol is known for. And the bad humidity we have. Plus ill be doors deep if I go threw the rivers down here and any moisture isnt good.
 

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i have a 1989 chevy blazer with 7" lift on 38x15x15 wheels with 700r4 with 373 rear swap. 350 std. bore and stroke with .275 dome piston with estimated 11.88:1 compression. I am budget building and wondering what the best cam to use would be. I have stock 193 heads that i will be porting. preferably a torque engine. i was looking at comp cams xtreme 4x4 cam with, 262° Intake / 270° Exhaust, Duration @ .050'' Lift:218° Intake / 226° Exhaust, valve lift with 1.5 rockers .462'' Intake / .480'' Exhaust, and 111 lobe separation. i guess what my question is. can my heads except this amount of lift and is this a good cam for my application. i am hoping for a lope noticeable idol. Its a weekend worrier not a daily driver and only sees road between mud holes. Any and all help would be beneficial.
The 193s are intended to get good gas milage at low RPMs in a heavy truck they aren't necessiarily meant nor do they create large low end torque numbers. Most any late model double quench, centered spark-plug, fairly modest port and valve size head will do that. What these heads really do is limit the upper RPM band. They gain very nicely to about 4300 then level off to about 5 then just quit. Figure that in your gearing and tire size.

If by porting you mean getting rid of the swirl vane you're on to something, they will wake up when ported but it's a lot of work. Check out castings 14096217 and 14011083 these are sold as cast iron L98 heads which is pretty much the same thing as the 193 with no swirl port vane to cut out. They are usually pretty cheap because nobody's looking for them. Heres where it gets tricky:

Part number 10159552 is the 55-86 version with 90 degree center holes, it is made from castings 14096217 or 14011083.

Part number 10125377 is the 1987 and up version with 72 degree center holes. It is made from castings 14096217 (sound familiar?) or 14101083 (watch this it's sooo close to above but it is different) these will fit your 89 TBI intake, or what ever intake you're running against the 193 heads.

All of these are 64 cc chambers with 1.96x1.5 valves and have a 170/175cc intake port. They are found on TPI and TBI passenger and cop cars including Camaro and Firebird.

A rebuilder may take your 193s as cores and save you some money.

Bogie
 

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I've built and dynoed a motor with those heads for a magazine engine build (see rat rod magazine #7 i believe) for their tour car in 2011.
used dished pistons and kept the compression way down for the lousy gas they find on tour. tested on 87 octane, we didn't pull big hp numbers but torque was 360. this was with a mild hydro cam, stock replacement style pistons with thick rings. stock valve sizes, and only a port match to clean up a messy pushrod area. even had a mismatched old edelbrock scorpion intake for that old school look.
keep the duration mild, these heads drop like a stone after 4500 rpms but used in this situation they have their merits.

currently building a 383 with these same heads for a nice 90's pickup used for towing. i have no doubt we'll go over 425 ft. lbs. on pump gas and a stock computer
 

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Discussion Starter · #13 ·
@hcomptin. We use up to 15% eth in all of our gas. Since they did that 3 years ago ive put a lot of fuel pumps in vehicles.
When it comes to intakes. I can use any I havent bought any yet. I will be carborating this engin. Had to many electrical issues with this truck. Also something to remember is this is a heavy vehicle. I weighs 6600 lbs. That is the main reason for the torque. We have a lot of hills and I want to be abble to drive up them without having to slow to 30 mph and I have no intention to go any higher than 5, 000 rpm. This block is not capable of hitting high rpm with it being 2bolt main and 268 block casting. I am just hoping to find what the max lift with new springs is for theese heads and what would be a good cam for my combination. I will most likely be removing the veins in theese heads.
 

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Discussion Starter · #16 ·
Horse power will be my by product. Torque is what I need in this combo. Horse power is a result of rpm and torque. If I keep a lower rpm I cam make more torque. Now im saying I wont be reving much over 5 even when it was stock I reved it to 6500 rpm and hit 8ooo once. I got csared, blew my trans. Im not planing on going much over 5 but It probably will. Im trying to get gobs of torque at a reasonable price and make it reliable and sound good.
 

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Discussion Starter · #17 ·
I can get them for free my friend bought new heads so im just asking if there better than what I have. Its a free head. With new springs and a port job will they be any better than my current heads for the application. It will help lower my compression to estimated 10.6:1. Which means possable sunoco 93
 

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Discussion Starter · #18 ·
I allredy have dome pistons in the bottom end .275 dome. +14cc dome. I would still be +8 cc over a stock 64cc with flat top. Thats the reason for thinking of goin with the 72cc. And they have to be better than 193 heads. I dont have 1400 to spend on new heads right now. So back to my question. 882 or 193? I will later be upgrading them but im currently on a budget. I have 350 set aside for cam lifters n springs. I have put to much into the bottom end to splurge on the rest and I must have this running by newyears. So for the next year. What am I better off with.
 

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IF- and that's a big if- you can expertly port the heads, use the swirl ports and hope for the best. The 883s are just not worth putting any time into IMO.

The problem here is you're asking what's better, a broken left leg or right leg. Neither are worth a timker's damn and using such a large domed piston isn't your friend, either.

If you insist on building this, as least avail yourself of the available info on quench and things to check in the valve train, including the geometry.

Also read up on cam break in procedures and setting up the distributor's advance curve.

Good luck. As the saying goes, you are gonna need it...
 

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Discussion Starter · #20 ·
I didnt relise that was a tag. My phone hylights random sentences if there is another forum about it. 600 for a pair ofxaluminum proformer heaes is good price. My only question is how cheap is the qluminum he is using. They look real thin. But I supose thats all questions for him. And with me. I dont mind running race gas. I wont be driving this vehicle much. Its a play toy. Maybe 100 miles a month if im lucky.
 
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