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Discussion Starter · #1 ·
Looking for mild streetable HP

68 396 325 HP with 215 heads

Planning:

.051 over bore (got a deal on .020 over 4.125 bore pistons) with Clevite TC3173 cast pistons with .180 dome, iron rings (not moly of chrome)
.039 head gaskets, no decking or head resurfacing
Summit k1301 218/228* dur @ .050 .500/.500 cam and lifters straight up.
stock intake with 650 cfm edelbrock
stock manifolds
msd hei
Cloyes roller timing set
New bearings all around
stock oil pump
valve seals and or guides

My questions are:
Am I ok for compression ration and pump gas?
Will the cam require a stall (68 SS396 with T400 and 17" wheels, 3:55 rear)?

Any info and or HP estimate is appreciated.
 

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With the stock heads you might want to bump your cam up to ensure it will run on pump gas. The most reccomended will be the Lunati 60203. I chose a custom grind that is a replica of the Edelbrock Torker. It is 224/232....527/553....114 LSA

My 69 440 block and 063 heads with stock intake and exhaust manifold are almost a mirror of your motor. My main consideration was drivability and low end torque. Running an A/C I did not want to sacrice idle or vaccum. I chose my cam over the 60203 because the 114 LSA gave me more of what I wanted over the 110 LSA of the 60203.
With stock manifolds I would not be able to use all of the 60203 in the upper end anyway.

First and foremost be absolutely certain of how you want to drive this car. No need to satisfy an ego building it beyond its intended use . At that point there is no turning back and it will probably disappoint you.
 

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Discussion Starter · #3 ·
Thanks for the info, I have been wrestling with the cam. I am looking for something pretty close or just a bit more than stock HP. I already havd a 500 HP 454 in the car now and this is a project with the kids to rebuild the original engine. The car is a numbers matching deal.

I have been considering pistons minus the dome although the stock ones I took out had a .180 dome with stock cam and it didn't detonate. I believe the factory compression was 10:25:1 so I am wondering if I would be ok. The factory cam was pretty small with short duration if I remember correctely.
 

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fresh engine with good compression, fresh valve job, new cam, etc, you might have trouble with pinging at 10.25 with iron heads and short cam. That was a premium fuel engine back when premium as 100 octane.
 

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Discussion Starter · #8 ·
Thanks Tom, if I am correct the 10:25 :1 is static compression. I used a dynamic compresion calculator and it indicated dynamic would be roughly 8:1. Is this correct?

fresh engine with good compression, fresh valve job, new cam, etc, you might have trouble with pinging at 10.25 with iron heads and short cam. That was a premium fuel engine back when premium as 100 octane.
 

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Discussion Starter · #9 ·
427L88- what do you mean by "not concerned about idle"? I could live with a bite of lope if thats what you mean. Does the longer duration mean less chance of pinging? I am trying to use a cam that will work with stock springs in the heads today.
 

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Discussion Starter · #10 ·
Update- Engine guys- pls comment on planned combination

Ok, here's an update with a few more questions, I have the engine back together with parts below.

What timing is recommended?

Should I use my hughes 2400 stall or go with the factory unit?

Will these clevite pistons lower my compression (dome is .123 and it has 2 valve reliefs). I'm wondering what my CR will be and if I will have any detonation issues..

HP estimate?



Thanks as always guys, this turned into a project with some local kids by the way. Theres at least 3 more kids who know what's inside a BB Chevy out there.

68 396 325 HP with 215 heads

.051 over bore (got a deal on .020 over 4.125 bore pistons) with Clevite TC3173 cast pistons with .123 dome, iron rings (not moly of chrome)
.039 head gaskets, no decking or head resurfacing
Summit k1301 218/228* dur @ .050 .500/.500 cam and lifters straight up.
stock intake with 650 cfm edelbrock
stock manifolds
msd hei
Cloyes roller timing set
New bearings all around
stock oil pump
valve seals and guides
valves ground




 

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I would say a slightly bigger cam in the 22X degree range at .050" and that 650cfm edelbrock seems a bit small. If you want an Edelbrock, I would suggest a 750/800cfm. I would size them a little bigger than if you were using a Holley, QFT, or BG carb.
 

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U should have no problem compression wise with the pistons and the heads U have listed. The compression ratio should be around 9.25-1 with the smaller.120 dome, basically like a 402 piston.
 

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cam that will work with stock springs
There is NO SUCH THING; not even a stock or stock replacement cam.

DO NOT hallucinate that you can put even something as tame as that Summit generic cam in there, under stock springs. Immediate, total, irrevocable, expensive destruction will be the certain result.

Whatever cam you use, even a stock one, REPLACE THE STOCK SPRINGS!!!! They absolutely cannot be used with aftermarket cams, for sure. No amount of wishing for it, complaining about the cost, reluctance to take something apart, etc. etc. etc. will convince the springs not to bind up their coils in a solid stack and wipe cam lobes, break push rods, bend rockers, etc. etc. etc. Not worth the time or effort. It's just going to have to be done. ;)
 

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Discussion Starter · #15 ·
My machine shop guy tells me the springs that were in there were not stock, he checked them in his shop and said they were within specs and would work with the cam I have. I am going to fire it up this weekend and will post here how it goes. Thanks for the info.

There is NO SUCH THING; not even a stock or stock replacement cam.

DO NOT hallucinate that you can put even something as tame as that Summit generic cam in there, under stock springs. Immediate, total, irrevocable, expensive destruction will be the certain result.

Whatever cam you use, even a stock one, REPLACE THE STOCK SPRINGS!!!! They absolutely cannot be used with aftermarket cams, for sure. No amount of wishing for it, complaining about the cost, reluctance to take something apart, etc. etc. etc. will convince the springs not to bind up their coils in a solid stack and wipe cam lobes, break push rods, bend rockers, etc. etc. etc. Not worth the time or effort. It's just going to have to be done. ;)
 

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Discussion Starter · #16 ·
Yea, I kinda figured the carb was on the small side but I'm only looking for a moderate cruiser and the carb worked well before the rebuild so I'm gonna give it a try. I'll post Monday and let you know how it goes. I'm going to pray to the cam lobe god prior to startup....

I would say a slightly bigger cam in the 22X degree range at .050" and that 650cfm edelbrock seems a bit small. If you want an Edelbrock, I would suggest a 750/800cfm. I would size them a little bigger than if you were using a Holley, QFT, or BG carb.
 

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Discussion Starter · #17 ·
Can anybody suggest timing values, initial and total for this combo please?

Looking for mild streetable HP

68 396 325 HP with 215 heads

Planning:

.051 over bore (got a deal on .020 over 4.125 bore pistons) with Clevite TC3173 cast pistons with .180 dome, iron rings (not moly of chrome)
.039 head gaskets, no decking or head resurfacing
Summit k1301 218/228* dur @ .050 .500/.500 cam and lifters straight up.
stock intake with 650 cfm edelbrock
stock manifolds
msd hei
Cloyes roller timing set
New bearings all around
stock oil pump
valve seals and or guides

My questions are:
Am I ok for compression ration and pump gas?
Will the cam require a stall (68 SS396 with T400 and 17" wheels, 3:55 rear)?

Any info and or HP estimate is appreciated.
 

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Forget all about what any Chilton or period tune-up book says.
Baseline of 16-18 initial with 36-38 deg total at 2800-3000
This will get you going. After that, experiment!!!! Each engine and car set-up is different!

You may have to take your distributor to a shop for a proper curve unless you know your own way around a Chevy distributor.
Got some EOS or Zinc additive in the oil?

Glad you shared the BBC Build Experience with some kids....

Edit:

See this thread, very similar:
http://www.chevelles.com/forums/showthread.php?t=234527
 

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Discussion Starter · #19 ·
UPDATE Fired it up: Engine guys- pls comment on planned combination

Well thanks again to all who commented on the build, fired it up last weekend and it worked out great. Fired right up, went to 2300 rpm adjusted timing to 30 degrees and ran it for 20 minutes. oil pressure is 40 at idle about 60 at 3000 Rpm. Vacuum is 16 at idle, timing 16 and 34 total. Was running abouit 200 degrees with a 195 stat, I put in a 165 last night and it stays steady at 175-180 (factory fan, shroud and rebuilt factory style radiator).

Doesn't smoke at all and drives nice, no unusual noises and ZERO leaks (so far) anywhere. After all the leaking stories I have heard on these engines I was pretty nervous but so far so good.

Used the 14w 40 rotella and lucas oil addative for break in, lots of assembly lube and prmed pump prior to startup. This was my first complete build up and it is a great feeling to drive the car and know what every piece in the engine is doing.

Thanks again for all the advice guys.
 

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:hurray::beers::hurray::beers::hurray::beers:

Great news!!!!

Where is the temp sensor? If in the head it will read a few degrees hotter than the intake.
Experiment with the timing....she'll likely respond to just a big more timing.

Now you are going to need to seat the rings.
Get on the throttle, let off
Repeat this a few times with progressively harder throttle application.
Change the break-in oil.
After that, clear sailing!
Enjoy.
I'm down to the garage to put my low-buck 454 together....
 
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