I have a '74 400 block bored with torque plates to .030 oversize. Have the new 17cc dished KB pistons fitted with Total Seal street rings. Stock rods re-sized and fitted with ARP bolts. Stock crank .010 undersize on the mains, .030 under on the rods. Pontiac Cam 068, 1.60 ratio roller rockers. HEI recurved w/MSD6A. Edelbrock Performer manifold and a big Q-jet from a buick. Reciprocating assembley is balanced.
Modified turbo 350 w/holeshot 2400 converter
Hopefully dynomax ceramicoat headers.(waiting for the specs on these before I buy)
All of this is going into my '80 T/A.
Now for the question: I bought a set of #16 heads for this engine to get the compression up. Hence the reason for the KB's, However upon closer inspection these heads have small valves (1.96 int./1.66 exh.). According to my HO parts and spec book this casting # is supposed to have large valves.
They came off a 1968 Catalina 400. Do I scrap these heads and keep searching or can these be used with my combo. I have already done the port matching and am ready to perform the street porting job. What should I do? Experiences? Ideas? Any help would be appreciated. Will these heads flow?

[This message has been edited by All4Fun (edited 05-13-2000).]

I have a '74 400 block bored with torque plates to .030 oversize. Have the new 17cc dished KB pistons fitted with Total Seal street rings. Stock rods re-sized and fitted with ARP bolts. Stock crank .010 undersize on the mains, .030 under on the rods. Pontiac Cam 068, 1.60 ratio roller rockers. HEI recurved w/MSD6A. Edelbrock Performer manifold and a big Q-jet from a buick. Reciprocating assembley is balanced.
Modified turbo 350 w/holeshot 2400 converter
Hopefully dynomax ceramicoat headers.(waiting for the specs on these before I buy)
All of this is going into my '80 T/A.
Now for the question: I bought a set of #16 heads for this engine to get the compression up. Hence the reason for the KB's, However upon closer inspection these heads have small valves (1.96 int./1.66 exh.). According to my HO parts and spec book this casting # is supposed to have large valves.
They came off a 1968 Catalina 400. Do I scrap these heads and keep searching or can these be used with my combo. I have already done the port matching and am ready to perform the street porting job. What should I do? Experiences? Ideas? Any help would be appreciated. Will these heads flow?

[This message has been edited by All4Fun (edited 05-13-2000).]

16s?Those would be a 68 GTO head.15's would be from a Bonnie,Cat,Ventura.Small valve/chamber.Compression would be around 10.25 from the factory.HP rating was 340 vs.350 on the 16 headed motor.If i remember correctly,the 15s are also press-in rocker studs.Now,the studs can be replaced with screw-ins,the heads can be made to accomodate the 2.11/1.77 valves.But you have to decide on the money/time factor.

[This message has been edited by Cobrabill (edited 05-12-2000).]

Thanks for the help Cobra, but these are definitly #16 heads. They do have the pressed in studs as I have already removed them (bottle-necked 3/8 top 7/16 bottom). I am sure they are late 60's as the end holes on the exhaust ports are not drilled. Which I also have to have done in order to accomodate the headers.

[This message has been edited by Todd (edited 07-18-2000).]

Thanks for the help guys! I checked with my machinist for a price quote on enlarging the valves. @$130.00 counting the blending. Seeing how I would have to have this done, the rocker stud pads tapped and the end holes on the exhaust ports drilled and tapped, plus the normal valve job, I decided to look around. Came upon a pair of 1970 #13 heads for $100.00. Needless to say I bought them and am starting to work them over. While I am pounding the key board, does this combo sound okay for a street performer or are there any ideas for improvement. Rear gears are to be 3.42 limited slip. Also live at 6000 ft. altitude. I would greatly appreciate any help or criticism.

[This message has been edited by All4Fun (edited 05-16-2000).]