As with all Procomp cylinder heads, our Big Block Chevrolet heads are Gravity Die Cast.
This casting process creates a much more uniform and robust cylinder head.
With the increasingly large displacements becoming common, the need for more airflow is
necessary.
If you are looking to build a 400-500+hp. engine, give our PC3021-396 heads a try.
They offer a smaller cross - section to increase the incoming air?s velocity, resulting in great driveability, power and economy.
On engines over 500hp., use the rectangle port PC3021 heads. The mid-size cross section works well on engines under 540cu.in. and under 7000RPM.
If you are working on a larger, or higher RPM engine, step up to the CNC ported PC3028 heads.
The added volume of the PC3028 intake ports ( 360cc ) helps to fill in the gap between As-Cast
performance heads and All-Out racing heads.
If you?re looking for 750+hp the PC3028-125XLVJ with their competition valvejob fit the bill perfectly.
| Finished Part No: | PC3021 |
| Valve Angle: | 24deg |
| Valve Springs: | 2.250' / 1.88' |
| Intake Volume: | 320cc |
| Chamber Volume: | 119cc |
| Comp. Valvejob: | No |
| Port Finish: | As Cast |
| Chamber Finish: | As Cast |
| Casting Material: | Alum. |
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Head Gaskets
Due to the wide combustion chamber needed to fit around the large 2.250/ 1.880" valves, we recommend our PC5211 MLS head gaskets.
These gaskets are .041" thick, and fit bore sizes as large as 4.540" on all Mark IV and VI blocks, as well as
aftermarket blocks.
Felpro 1017 gaskets will also work with these head/ block combos.
To install our BBC heads on Mark V blocks, you will need to use our PC5233L and PC5233R Elite Series MLS head gaskets.
Alternatively, you can use Victor Reinz # 4918(R) & #4923(L) head gaskets on Mark V blocks with our heads.
Intake Gaskets
The PC3021 heads work well with our PC3289 rectangle port gaskets.
The PC3021-396 heads require our PC3290 oval port gaskets.
If you prefer Felpro gaskets, the PC3021 heads take a 1275 or 1275-5 gasket, depending on the thickness you require.
The CNC-ported heads (PC3028-125) are matched to the Felpro 1275 & 1275-5 gaskets.
Push Rods
Our aluminum 23deg. heads typically use +.100' (longer than stock) pushrods.
Depending on the components used, it is possible that you may need pushrods shorter or longer than that so we recommend that you use an adjustable pushrod to dial in your rocker geometry and order pushrods to match.
Spark Plugs
Our heads require the use of 14mm. x 3/4" reach 5/8" hex gasket seat sparkplugs.
Some recommended plugs are; NGK BCPR6ES or R5671A-7, Champion RC12YC, Autolite AR3923 or AR3924.
Remember these are for mild street engines. Higher compression or boost requires colder sparkplugs!
Head Bolts / Studs
Due to the raised (+.625") exhaust port location on our heads, +.100" longer bolts / studs are needed next to each port.
Use our pn# PC2452-6100 Headstud Kit. ARP #135-3703 12pt. Headbolts, and #235-4303 Headstuds work too.
If you already have a standard BBC headstud kit and are just looking for the 8 +.100" studs, use our
pn#2452-6100-8 or ARP # 235-4306.
These heads should be torqued to 65ft.lbs. using high pressure moly lube or 70ft.lbs. using 30wt. oil.
Exhaust Gaskets
Our BBC heads utilize a 1.88" x 1.88" square exhaust port.
This exhaust port requires specific gaskets.
Our pn# PC5202 gaskets are made of re-useable copper, or if you prefer paper, use our pn# PC5123.
Felpro also offers gaskets that work with our heads as # 1410.
