Second guessing cam change
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
As an aside, get the cam valley and deck sprayed down with a bit of WD-40, and get some rags in that cam valley. Too easy to drop junk in the engine when it's that open.
Thread Starter
Instructor
Joined: May 2007
Posts: 130
Likes: 0
From: Houston TX
billa
Many thks for your time and input. I'll do the "deck check" again and let you know. Should make for a better CR calc....and offset the added cc for valve reliefs. Using 10cc and est. the deck height back to 0.025 I come up with a CR of about 9.1 with a 0.028 gasket. That should also lower the DCR to more "pump gas" operation.
I realize these heads are not ideal but will be a big improvement over the "smoggies" I took off. If I can get a solid 325-350 torq and 300+hp I'll be happy...for now...we'll see.
Thks, again.
Will report back when all together.
Many thks for your time and input. I'll do the "deck check" again and let you know. Should make for a better CR calc....and offset the added cc for valve reliefs. Using 10cc and est. the deck height back to 0.025 I come up with a CR of about 9.1 with a 0.028 gasket. That should also lower the DCR to more "pump gas" operation.
I realize these heads are not ideal but will be a big improvement over the "smoggies" I took off. If I can get a solid 325-350 torq and 300+hp I'll be happy...for now...we'll see.
Thks, again.
Will report back when all together.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Good luck, have fun, post pictures
Thread Starter
Instructor
Joined: May 2007
Posts: 130
Likes: 0
From: Houston TX
I'm about to install these World heads I bought on eBay. It turns out they are Sportsman II with large runners (?) and big springs. Don't have the spring specs but concerned they may be TOO big for my hydraulic flat tappet cam and lifters.
IS there a max rate, limit, on what the flat tappet cams can handle?? Lunati instructions warn against using wrong springs but don't list a rate limit.
They are dual springs, outside spring O.D. 1.55", which appears to be same as Comp Cams dual springs with 352#/" rate...but dont' know and don't know how to check.
IS there a max rate, limit, on what the flat tappet cams can handle?? Lunati instructions warn against using wrong springs but don't list a rate limit.
They are dual springs, outside spring O.D. 1.55", which appears to be same as Comp Cams dual springs with 352#/" rate...but dont' know and don't know how to check.
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
sounds like a fun experiment(to test that idea going around that u can't go too big on heads)
somebody has to put 200cc sportsmans, a smallish cam, and 308's and drive this in the winter! with huge springs! gotta push the envelope
somebody has to put 200cc sportsmans, a smallish cam, and 308's and drive this in the winter! with huge springs! gotta push the envelope
Thread Starter
Instructor
Joined: May 2007
Posts: 130
Likes: 0
From: Houston TX
I've (somebody) been discovered...paying for big heads to see how they work with a smallish cam. Money's no object to us oil barons her in TX.
Appreciate any constructive comments rather than pointing out the obvious. Is that due to salt air, or just air.
After trying to get these heads bolted on and valves set, I found the roller tip rockers bump on the spring O.D., so will have to change them or go to full rrkrs and larger covers. My ecomomy World heads are getting very costly because there was too little info furnished and I made some false assumptions. Sportsman IIs not S/R Torquers...big diff.
Now I've got the mess this other somebody has so correctly described.
So, what's next...1) Change the heads; 2) change just the springs; 3) change the springs, the cam and intake to match the heads...or, 4) Put the orig crap back on and sell it, then buy a C5!??
Maybe I'll just do some more experimenting..."tomorrow's another day, Scarlet."
Appreciate any constructive comments rather than pointing out the obvious. Is that due to salt air, or just air.
After trying to get these heads bolted on and valves set, I found the roller tip rockers bump on the spring O.D., so will have to change them or go to full rrkrs and larger covers. My ecomomy World heads are getting very costly because there was too little info furnished and I made some false assumptions. Sportsman IIs not S/R Torquers...big diff.
Now I've got the mess this other somebody has so correctly described.
So, what's next...1) Change the heads; 2) change just the springs; 3) change the springs, the cam and intake to match the heads...or, 4) Put the orig crap back on and sell it, then buy a C5!??
Maybe I'll just do some more experimenting..."tomorrow's another day, Scarlet."
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Change to the matching springs.
What's the Sportsman head chamber cc?
Assuming cam in your first post,
"Lunati 60101, 213/219, .454/.468"
& engine in very good cond. on dyno w/ headers you will exceed your goals.
Assuming cam in your first post,
"Lunati 60101, 213/219, .454/.468"
& engine in very good cond. on dyno w/ headers you will exceed your goals.
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Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
Scoggin Dickey has Aluminun E-streets for 850+shipping. 2.02/1.60, 185cc runners, 64cc chambers. bolt and go. No EGR. work perfect with a 2101 mani.
http://www.sdparts.com/product/E5089...Heads64cc.aspx
http://www.sdparts.com/product/E5089...Heads64cc.aspx
Thread Starter
Instructor
Joined: May 2007
Posts: 130
Likes: 0
From: Houston TX
Thanks for the feedback. Had thought to change springs but didn't think to use my old retainers...a good $$ suggestion, thanks, much. And, that would allow me to use the rkrs I have.
What about using a 1.6 ratio true roller rkr which would work with the springs and give me more lift, by my calc .484/.499?? A little more $$ but less work and more lift.
The SII runners are 200cc...and the heads are on with cam in. Used a thin Fel-Pro, #1094 to gain CR. Now considering the Performer manifold to try to match the runners.
Performer RPM would be even better, but I don't think it will fit under the stock hood.
What about using a 1.6 ratio true roller rkr which would work with the springs and give me more lift, by my calc .484/.499?? A little more $$ but less work and more lift.
The SII runners are 200cc...and the heads are on with cam in. Used a thin Fel-Pro, #1094 to gain CR. Now considering the Performer manifold to try to match the runners.
Performer RPM would be even better, but I don't think it will fit under the stock hood.
Thread Starter
Instructor
Joined: May 2007
Posts: 130
Likes: 0
From: Houston TX
Thks, agree. Have determined big springs are roller size, over 2" installed ht. Will probably go with the Lunati recommed. #73943. O.D. same as old ones so I should be able to use the old ret.
Also, orig chamber for this head is listed as 64cc, seller indicates 67cc. Don't know if that reflects addl work along with reported "porting on intake and exhaust".
Anyway, using 67cc, deck clearance 0.040"(micro chkd), +10cc for valve reliefs and 0.015 gasket I come up with a CR of about 9.1:1. Or, 9.3 if 64cc chamber.
At 9.1:1 CR, "mild porting", and the Lunati 60101 cam the Virtual Dyno says 370# torque and 363 HP...!!
However, I'm expecting my stock intake is now the limiting factor. That's the reason for the question on the use of the Edelbrock Performer or Perf RPM.
Also, orig chamber for this head is listed as 64cc, seller indicates 67cc. Don't know if that reflects addl work along with reported "porting on intake and exhaust".
Anyway, using 67cc, deck clearance 0.040"(micro chkd), +10cc for valve reliefs and 0.015 gasket I come up with a CR of about 9.1:1. Or, 9.3 if 64cc chamber.
At 9.1:1 CR, "mild porting", and the Lunati 60101 cam the Virtual Dyno says 370# torque and 363 HP...!!
However, I'm expecting my stock intake is now the limiting factor. That's the reason for the question on the use of the Edelbrock Performer or Perf RPM.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Previous 2101 is good for over 400hp, so you could use 2101 or Weiand Action+ w/ Q-J (stock air cleaner clears) or Holley.
SEE http://forums.corvetteforum.com/c3-t...er-intake.html
The RPMs should fit w/ aftermarket dropbase filter & Holley as lowest point is in front.
RPMs fit w/ the 73-79 med. rise hood.
SEE http://forums.corvetteforum.com/c3-t...er-intake.html
The RPMs should fit w/ aftermarket dropbase filter & Holley as lowest point is in front.
RPMs fit w/ the 73-79 med. rise hood.
Race Director
Joined: Oct 2000
Posts: 14,994
Likes: 79
From: central FL, near the beach.
do u have any dyno charts of that cam?
big heads work great 3000+ rpm.
if the cam rolls over at 5300
the RPM intake won't help until ~4500+.
the small intake will help increase velocity/atomization idle-5500
i have 190cc heads on my 61-355 with 2101, i have no complaints w/warm engine. keep the 2101 imo, as long as u have the small cam. The 1.6 rockers are a MUST with this combo imo. They will have the effect of adding ~2 degrees which it really needs.
big heads work great 3000+ rpm.
if the cam rolls over at 5300
the RPM intake won't help until ~4500+.
the small intake will help increase velocity/atomization idle-5500
i have 190cc heads on my 61-355 with 2101, i have no complaints w/warm engine. keep the 2101 imo, as long as u have the small cam. The 1.6 rockers are a MUST with this combo imo. They will have the effect of adding ~2 degrees which it really needs.
Thread Starter
Instructor
Joined: May 2007
Posts: 130
Likes: 0
From: Houston TX
Matt, thks. Confirms the RPM is way more than I need for a strong street car, rarely over 4500rpm.
Also, there seems to be little to lose and some to gain using the 1.6 rkrs w/ the Lunati 60101, and 2101 intake. I'll need a spring with a max travel of 0.500 or greater.
Thks, again.
Also, there seems to be little to lose and some to gain using the 1.6 rkrs w/ the Lunati 60101, and 2101 intake. I'll need a spring with a max travel of 0.500 or greater.
Thks, again.
Thread Starter
Instructor
Joined: May 2007
Posts: 130
Likes: 0
From: Houston TX
Update on this project that many of you helped me with.
During the last three weeks I've had the World heads rebuilt with new Lunati springs, and a valve job with new guides. The valves had "long" stems that required a tall spring with cups and shims to set up for correct height, seat load, etc. Recently completed the installation of the heads with Comp 1.6 magnum roller tip rkrs, 100 long hardened rods with guides. Now adding accessories and should be ready for the break-in run sometime tomorrow.
I used a Fel-Pro shim gasket 0.015in with the deck ht of 0.040in to keep the CR at 9.3:1 (have dbl valve reliefs that add~10ccs).
The 1.6 rkrs should make a little more power from the Lunati 60101 cam
More w/pics when engine and/or project is complete.
During the last three weeks I've had the World heads rebuilt with new Lunati springs, and a valve job with new guides. The valves had "long" stems that required a tall spring with cups and shims to set up for correct height, seat load, etc. Recently completed the installation of the heads with Comp 1.6 magnum roller tip rkrs, 100 long hardened rods with guides. Now adding accessories and should be ready for the break-in run sometime tomorrow.
I used a Fel-Pro shim gasket 0.015in with the deck ht of 0.040in to keep the CR at 9.3:1 (have dbl valve reliefs that add~10ccs).
The 1.6 rkrs should make a little more power from the Lunati 60101 cam
More w/pics when engine and/or project is complete.
