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Old 10-06-2002, 05:06 PM
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Post 1.94 heads or 2.02

i am going to buy remanufactured heads for my 350 chevy pickup. what is the diffference in 1.94 and 2.02 heads besides the valves. Which is better. P.S. my bottom end has probaly 70,000 miles

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Old 10-06-2002, 05:28 PM
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Going to a 2.02 intake does not always equate to more power, especially if the head is not prepped properly to accept the valve. On the intake side, it is very important that the combustion chamber is unshrouded either by grinding or using a fixed cutter when the valve job is done. Also , the valve pocket should be ported and blended into the seats.
Anyway, to answer your question, larger valves can help power, by increasing the circumference of the seat area, thereby increasing low and mid lift flow as well as the larger lift "window" at maximum valve lift.
Not all engines need bigger valves, on a truck like yours, if it's a daily driver, you probably wouldn't notice a difference between the 1.94s VS 2.02s if all other factors were equal. Probably a few ponies, but nothing that would flatten your eyeballs.
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Old 10-06-2002, 05:40 PM
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A 1.94 intake valve will generally make better low end power and torque than a 2.02 valve. The 2.02 valve seems to work better at higher RPM's.

Seeing as you are installing the heads on a truck, I would think that the 1.94 valve would be a better choice.

Even a stock 400 cubic inch Chevrolet comes with a 1.94 intake valve.

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Old 10-06-2002, 08:06 PM
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Thanks alot guys. Is there any way to tell what size valves i have now? My heads show too types of valves 194 and 202's. Im not sure what i have does the 160 number after the 2.02 mean 1.6 rockers. cause i have 1.5s. does that tell me anything.
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Old 10-06-2002, 08:18 PM
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As a rule, 1.60 when used with 2.02 means 1.60 exhaust valve.

2.02 in plain English means that the valve measures 2 inches and 20 thousands or 2 inches and 1/50 th of a inch.

1.60 in plain English means that the valve measures 1 inch and 600 thousands or 1 inch and 6/10 of a inch.

There are rocker arm ratios of 1.5 to 1 and 1.6
to 1 available for the small block Chevrolet.
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Old 10-06-2002, 09:12 PM
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New top-end & 70,000 miles on bottom end, I'd be ckecking out the bearings, I've always been told if you do the top end and leave the bottom alone, the new top will pound the bottom out and visa-versa. For the amount of time it takes to ckeck and if it needs it, put in new bearings in. I'd look at least. Oh yeah and go with the 1.94's unless you plan to pull big revs.


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Old 10-07-2002, 06:57 AM
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Thansk guys putting just a valve job on my heads wont hurt my bottom end will it? Will it give me more power/
thanks again
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Old 10-07-2002, 12:14 PM
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If you're gonna go to the trouble to pull the heads then you should do the rest of it. An engine that manages to stay unopened will run about 200,000 miles before it gives up. Once things get opened up and the balance of wear is disturbed things seem to go down hill in a heartbeat. (Snicker)

Try <a href="http://www.enginekits.com" target="_blank">http://www.enginekits.com</a>

They can set you up with the extras you need for under $100. Or you may spend as you will.

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Old 05-23-2013, 04:40 PM
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New here;

I have a 94' 5.7 4 bolt. It did have TBI, I put an edlebrock performer with a 600 edle carb. Like others I was thinkin bout swappin heads, I heard that the TBI heads are the worst ones you can have, anyway these heads have the 1.94/1.50 valves. My question is can you pull the rocker studs[ pressed in] and put in threaded studs for roller tip rockers? Thanx and keep the tire smoke rollin!!
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Old 05-23-2013, 04:59 PM
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Quote:
Originally Posted by cajinlobo View Post
I have a 94' 5.7 4 bolt. It did have TBI, I put an edlebrock performer with a 600 edle carb. Like others I was thinkin bout swappin heads, I heard that the TBI heads are the worst ones you can have, anyway these heads have the 1.94/1.50 valves. My question is can you pull the rocker studs[ pressed in] and put in threaded studs for roller tip rockers? Thanx and keep the tire smoke rollin!!
My understanding is that TBI are great for producing torque. The downside is that they aren't much good above 4,000 RPM's.

Yes you can install screw in studs. Do you need screw in studs just because you have roller rockers? No. You would need screw in studs if you replace your cam and it has very aggressive spring pressure requirements. But if you replace the rockers, then you would need to verify pushrod length is correct, and buy new pushrods as necessary.
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Old 05-23-2013, 06:38 PM
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Quote:
Originally Posted by cajinlobo View Post
I have a 94' 5.7 4 bolt. It did have TBI, I put an edlebrock performer with a 600 edle carb. Like others I was thinkin bout swappin heads, I heard that the TBI heads are the worst ones you can have, anyway these heads have the 1.94/1.50 valves. My question is can you pull the rocker studs[ pressed in] and put in threaded studs for roller tip rockers? Thanx and keep the tire smoke rollin!!
A 94 was a Swirl Port, TBI engine. These are two versions of this engine with the same installtion code but you can usually tell by the vehicle's gross weight. If over 8700 pounds it will have the 191 head with 76 cc chambers and the valves will be 1.94x1.50. under 8700 pounds gross it will have 193 heads that have a 64 cc chamber and 1.94x1.5 valves. Both engines use the very low performance high torque cam with 166/175 I/E timing and .382/.401 inch I/E lift at the valve.

Chevy changed the angle of the center 4 intake bolts from 90 to 72 degrees in 1987. Since you have a 72 degree intake you'll need to shop for that center bolt angle or an intake that matches the angle on the new heads.

The rockers are self aligning, you need to buy that type rocker or go to a wholesale change to use the non-self aligning rocker. Yes the studs can be pulled and the the boss tapped for a screw-in stud but the boss has to be machined down for the thickness of the hex on the stud. Add to that if you convert to non-self aligning rockers you will have to add push rod guide plates which will also require that the boss be machined down further for their thickness as well. This will also require hardened push rods. The soft type in the engne now will dissappear pretty quickly when rubbing the guide.

The 2.02x 1.6 inch valves of a new head probably won't make a difference you can feel unless you change the cam and increase the compression. Before you buy a camshaft or push rods you need to look into the valley to see if this engine has a roller or flat tappet cam. This can be seen from a valve cover removal by shining a strong light into the valley area through the push rod gaps; if the lifters are not joined in pairs with what's called a dog bone, then it is a flat tappet engine and takes the ordinary GM flat tappet parts in the valve train. If there are dog bones then this would have a roller cam and all the valve train parts are unique to that design. Now let me say that it is extremely rare that a truck will have a roller cam in the block, but it happens, so check before you put down money for a camshaft, lifters and pushrods.

Bogie
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