1985 questions
Thread Starter
Heel & Toe
Joined: Sep 2004
Posts: 18
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From: Fallbrook Ca
1985 questions
Ok, 2nd time vette owner (had an 87) 1st post. After doing an exhaustive search on all the wealth of knowledge on this site i'm finally posting. Has anyone put 113 heads on a stock iron-head L98 and what were the benefits? I believe the stock cc's of the iron heads are 64cc and the al are 58. So CR /HP/ TQ benefits and any smog issues/compatabilities? Also looking to replace original ignition components in near future - suggestions? How difficult would it be to upgrade block to use roller cams and lifters. 1985 4+3 w/ 83000 original miles. Thanks.
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
If I was doing all of that, I would consider getting a used block and building it up outside the car, then dropping in the finished product.
The 85 is a 2 pc rear main... I am not sure how the older blocks work with roller lifters, but I am sure someone has a retrofit kit if they don't just drop in. The cam is different, but should still fit.
The 113s won't give you any emissions problems. They are legal heads already! But with the earlier pistons? As long as the cats are working, you won't have a problem.... also, compression won't have as much impact on emissions as a lot of cam would.
Welcome to the forum!!!
The 85 is a 2 pc rear main... I am not sure how the older blocks work with roller lifters, but I am sure someone has a retrofit kit if they don't just drop in. The cam is different, but should still fit.
The 113s won't give you any emissions problems. They are legal heads already! But with the earlier pistons? As long as the cats are working, you won't have a problem.... also, compression won't have as much impact on emissions as a lot of cam would.
Welcome to the forum!!!
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
The 113 heads will bolt right on, but there are a few concerns. Your iron 624 heads have 76 cc combustion chambers, not 64 ccs. The change to 58 ccs will really bump up your 9.0:1 compression ratio. The iron heads feed exhaust gases to the intake manifold for the EGR. If you want to keep the EGR functional, you'll have to use a later intake and exhaust manifold to feed the exhaust via the external tube. The iron heads are pretty poor. They're the same as on my Crossfire. The 113 aluminum heads are a great step up. Beside the compression boost, they breath much better and will make a good foundation for future up grades. Just do the math and watch the compression ratio.
RACE ON!!!
RACE ON!!!
Thread Starter
Heel & Toe
Joined: Sep 2004
Posts: 18
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From: Fallbrook Ca
So would the accel/SR base would work with the egr issue as that's the plan for the future as well as the 219/w Upper SR Plenum and Runners? Has anyone done this on an 85 and kept the bottom end stock?
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
The stock bottom end is as good or better than anything that came after it. The block isn't set up for the OEM factory roller lifters, but you can use retro fit lifters or modify the block to take Chevy lifters. No later L98 has the forged pistons yours has.
You don't mention whether you want to keep the EGR or not. IF the SR has the EGR (I believe it does), it will be compatible with the 113 heads and NOT your present 624s. You would have to feed the exhaust gases from a later model exhaust manifold, modify your manifold, or use 1986-up headers with EGR provisions. Go for it!
RACE ON!!!
You don't mention whether you want to keep the EGR or not. IF the SR has the EGR (I believe it does), it will be compatible with the 113 heads and NOT your present 624s. You would have to feed the exhaust gases from a later model exhaust manifold, modify your manifold, or use 1986-up headers with EGR provisions. Go for it!
RACE ON!!!
Instructor
Joined: Aug 2003
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Vortecs???
Squid: Maybe the Chevy Vortecs and a new intake are something you'd want to check out. Scoggins-Dickey has the heads and head/intk. packages. Apparently they flow well but req. a change in intake for compatibility. Pricewise maybe as good as your other options but with better improvement(?) Just a consideration you may want to think about. Squid????????????????
Thread Starter
Heel & Toe
Joined: Sep 2004
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From: Fallbrook Ca
Thanks for the advice. Since i'm in Cali I need to keep it smog friendly. I checked out SD - good prices, and i'll consider it. What i really need to know is if the 58CC chamber on a 113 will be to small - something like 11 to 1, on 91 octane?????? I would think that if you raise comp you increase HP and TQ, so this would be the easiest and most beneficial way to do so with my stock shortblock. I want to keep the bottom end stock due to the Factory forged pistons. Has anyone gone this route or have any expierence with precision porting???? Thanks again.
Squid = Navy
Squid = Navy
Le Mans Master
Joined: Apr 2000
Posts: 6,341
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From: Shelton CT
I have 117K miles on my stock bottom-ended '85.
I was going to swap to a set of ported 113's, but the whole mess with the egr (I wanted to keep it emissions legal too), made me chose another set of heads that have the same EGR 'plumbing' as stock.
The accel lower base has provisions for both EGR setups. internal ala '85, and external ala 86 1/2+ years. Other than that, I am very happy with my '85 and the way she performs.
I personally would not jump up to 58cc chambers as that would bring your compression to 10.5-11.0 and you'd pretty much either use ONLY 93 octane, or never ever floor it if you use lower octane gas. (Or you could retard the timing a bit until she stops pinging, but then lose HP.)
I stuck with 64cc chambers and they work pretty well..
I was going to swap to a set of ported 113's, but the whole mess with the egr (I wanted to keep it emissions legal too), made me chose another set of heads that have the same EGR 'plumbing' as stock.
The accel lower base has provisions for both EGR setups. internal ala '85, and external ala 86 1/2+ years. Other than that, I am very happy with my '85 and the way she performs.
I personally would not jump up to 58cc chambers as that would bring your compression to 10.5-11.0 and you'd pretty much either use ONLY 93 octane, or never ever floor it if you use lower octane gas. (Or you could retard the timing a bit until she stops pinging, but then lose HP.)
I stuck with 64cc chambers and they work pretty well..
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Instructor
Joined: Aug 2003
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Comp. Ratio
Squid:
Have you used a reliable formula to figure the c.r.? Input the REAL data? (ex., deck height)? If not, maybe your actual c.r. would be less than anticipated(your prior post).
How about the thickest head gasket available? (again, an "input data
variable).Don't know if a home-made "flycutter" would be possible to use to enlarge the piston "eyebrows" IN THE ENGINE. (use an old scrap head as a guide w/ flycutter made of old valve w/ welded cutter??
If the car's an occassional driver maybe octane booster is an alternative. I believe about 10:1 w/ iron heads is max. cr for 93 octane.
P.S.- I think the eyebrows present now(??) if present, would be about 4 cc's total each piston.
Have you used a reliable formula to figure the c.r.? Input the REAL data? (ex., deck height)? If not, maybe your actual c.r. would be less than anticipated(your prior post).
How about the thickest head gasket available? (again, an "input data
variable).Don't know if a home-made "flycutter" would be possible to use to enlarge the piston "eyebrows" IN THE ENGINE. (use an old scrap head as a guide w/ flycutter made of old valve w/ welded cutter??
If the car's an occassional driver maybe octane booster is an alternative. I believe about 10:1 w/ iron heads is max. cr for 93 octane.
P.S.- I think the eyebrows present now(??) if present, would be about 4 cc's total each piston.
Racer
Joined: Mar 2004
Posts: 311
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From: Oakley Ca
With a .041 gasket my engine sim says 10.4 compression for the 113's. Prolly won't run on regular. To save a lot of hassel use TFS 195's as they have egr provisions and 64 or 72 cc chambers. If I'm doing the sim correctly the 64 cc chambers yield 9.71 and 72 cc will yield 8.94. I would advise the 72 cc heads. Others will disagree, but, the price of gas is going up every day so use regular and if you go to 383 later you'll be glad you did. The flow of these heads will more than make up for the lower compression. As stated earlier the accel base is set up to use both styles of EGR. Just my thoughts.
Instructor
Joined: Feb 2005
Posts: 125
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From: york pa
the only problem i see is what about engine managment?I,m in the same boat i cant find anyone who can program the 85 i either have to upgrade to a newer factory computer and wire harness or go with an aftermarket fuel injection or carb
Le Mans Master
Joined: Apr 2000
Posts: 6,341
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From: Shelton CT
Originally Posted by M.Clough
the only problem i see is what about engine managment?I,m in the same boat i cant find anyone who can program the 85 i either have to upgrade to a newer factory computer and wire harness or go with an aftermarket fuel injection or carb
Racer
Joined: Mar 2004
Posts: 311
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From: Oakley Ca
Originally Posted by M.Clough
the only problem i see is what about engine managment?I,m in the same boat i cant find anyone who can program the 85 i either have to upgrade to a newer factory computer and wire harness or go with an aftermarket fuel injection or carb
The Accel and TPIS bigmouth manifolds are the same.
Thread Starter
Heel & Toe
Joined: Sep 2004
Posts: 18
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From: Fallbrook Ca
BlueVette85,
How much are your heads ported? I have decided to go with Precision Porting and Coating's stage 3 heads, Now I just need to save $$$ . Why did you go with the 113 cam instead of the 119?
How much are your heads ported? I have decided to go with Precision Porting and Coating's stage 3 heads, Now I just need to save $$$ . Why did you go with the 113 cam instead of the 119?
Drifting
Joined: Nov 2001
Posts: 1,783
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From: Latham NY
Originally Posted by Calsquid
BlueVette85,
How much are your heads ported? I have decided to go with Precision Porting and Coating's stage 3 heads, Now I just need to save $$$ . Why did you go with the 113 cam instead of the 119?
How much are your heads ported? I have decided to go with Precision Porting and Coating's stage 3 heads, Now I just need to save $$$ . Why did you go with the 113 cam instead of the 119?
I bought them from Total Engine Airflow but don't have flow data. I'm rebuilding the engine so I have them tested soon.
The 213 cam is for hydraulic lifters. My 85 block can't take the 219 cam without a conversion or retrofit.
Check out John Lingenfelters book "Modifying Small-Block Chevy Engines". It has lots of information.
Thread Starter
Heel & Toe
Joined: Sep 2004
Posts: 18
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From: Fallbrook Ca
Have the book and that's what really convinced me to go with the 113's. I only use 91 octane in mine so i guess the compression will be no problem. Have you gotten your car dynoed? I'll bet it's night and day from stock. My goal is to eventually get 400CHP+ out of the motor N/A on the stock shortblock. Thanks for the info everyone. 