85 C4 planned upgrades...
Thread Starter
Cruising
Joined: Apr 2013
Posts: 11
Likes: 0
A bit of a setback......with Promaxx heads....
We had a delay in the shipment of the fresh block from Summit, but it came in about 2wks ago, and we were eager to get started.
Got the bottom buttoned up and started to mock up the top, to see if the pushrods will still work with the new cam and 1:6 roller rockers.
Popped a gasket on the intake and ...Hello! Intake ports do not match the gasket. Runners in the heads are located too high...
Placed the intake on, and you could see the gap on the top of the intake runner.
Contacted Summit, sent them some pics,they never heard of this before... and gave me the contact for Promaxx.
The contact at Promaxx proceeded to tell me that these are performance heads and I needed some "special" gaskets or switch intakes...
Well neither of those was going to happen. Doing some searching I came to the conclusion that the intake port location is the same as on a Vortec head, yet the head uses the "old" intake bolt pattern.
This was something not listed on the Summit site...
The heads went back to Summit, and a set of E-Streets just arrived today. A slight bit more $, but made in the USA
.
Now I need to check the springs on these heads to make sure they are suitable for the cam.
We'll carry on..
Bart
Got the bottom buttoned up and started to mock up the top, to see if the pushrods will still work with the new cam and 1:6 roller rockers.
Popped a gasket on the intake and ...Hello! Intake ports do not match the gasket. Runners in the heads are located too high...
Placed the intake on, and you could see the gap on the top of the intake runner.
Contacted Summit, sent them some pics,they never heard of this before... and gave me the contact for Promaxx.
The contact at Promaxx proceeded to tell me that these are performance heads and I needed some "special" gaskets or switch intakes...
Well neither of those was going to happen. Doing some searching I came to the conclusion that the intake port location is the same as on a Vortec head, yet the head uses the "old" intake bolt pattern.
This was something not listed on the Summit site...
The heads went back to Summit, and a set of E-Streets just arrived today. A slight bit more $, but made in the USA
.Now I need to check the springs on these heads to make sure they are suitable for the cam.
We'll carry on..
Bart
Thread Starter
Cruising
Joined: Apr 2013
Posts: 11
Likes: 0
It lives...
Had a great weekend, great weather and got the car back up and running again.
Wow, what a difference....I can't wait to get past the break in time...
So the whole (re)build was:
- ATK 350 short block, .040 over, hypereutectic flat top pistons. .019" deck height.
- Edelbrock E-street Alu heads, 185cc runners, 64cc combustion chamber.
- .015" Felpro Q1094 headgaskets
- ARP headbolts.
- Comp Cams 1.6:1 full roller rockers.
- Crane hardened pushrods, stock lenght.
- Comp Cams K12-256-4 Cam Kit (lifters, roller timing set etc) installed straight up.
http://www.compcams.com/Company/CC/c...x?csid=91&sb=2
- Headman Hedders
- Accel Street Ram intake, runners, plenum.
- Streetpro harmonic balancer.
- Mini starter.
Calculated CR ratio of 10.5:1.
Wow, what a difference....I can't wait to get past the break in time...
So the whole (re)build was:
- ATK 350 short block, .040 over, hypereutectic flat top pistons. .019" deck height.
- Edelbrock E-street Alu heads, 185cc runners, 64cc combustion chamber.
- .015" Felpro Q1094 headgaskets
- ARP headbolts.
- Comp Cams 1.6:1 full roller rockers.
- Crane hardened pushrods, stock lenght.
- Comp Cams K12-256-4 Cam Kit (lifters, roller timing set etc) installed straight up.
http://www.compcams.com/Company/CC/c...x?csid=91&sb=2
- Headman Hedders
- Accel Street Ram intake, runners, plenum.
- Streetpro harmonic balancer.
- Mini starter.
Calculated CR ratio of 10.5:1.
Thread Starter
Cruising
Joined: Apr 2013
Posts: 11
Likes: 0
Edelbrock does a nice job on these heads. Quality hardware that includes the guide plates, rocker studs, spring cups etc. The installed springs are 1.5"dia and are good for mild flat tappet applications.
Intake ports are lightly cnc machined as are the exhaust. Intake and exhaust runners were "clean" for a cast finish.
Team Owner
Joined: Sep 2001
Posts: 62,160
Likes: 1,733
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
My 86's TC worked fine behind a 398 SR engine, as did the rest of the tranny, but it'll blow eventually.
