A couple years ago I picked up a "fresh" 390 that had less than 500 miles on the clock.

It was bending pushrods and was waaaaay down on power.

It was a total beginner doing the install etc and things were pretty screwed up.

When it started running rough about the 3rd time he just pulled out the engine and scrapped the truck.

When I pulled off a valve cover I found a broken rocker shaft and a couple bent pushrods.

It was actually going into coil bind on the springs causing the issue, close but at higher rpm is when the issue arose.


A few months back I decided to "freshen" it up and at time of teardown found the pistons had .120 deck clearance, typical with a 360 style piston.

Compression ratio was also under 8.0 to 1

It was a late '67 block with a '68 passenger car serial number on it. Block was obvious a fresh .030.

I had a "spare" 1 of 3 extra 1U cranks laying around so decided to just drop in the 428 crank which would have gotten me around .020 deck clearance.

Fine enough for pickup truck street use. I could just re-ring it, freshen up the heads and use it.

Heads were C8AE-H's

It had a new looking Edel Perf 390 intake on it

 

I really wanted to have a final hone with deck plates but upon measuring the bores it was already .005 too large for the pistons.

I then did a sonic check and found plenty of room to go .040

Upon inspection of heads found the seats needed replacing.
Of course the wheels were really spinning in my head at this time.

Not wanting to go the 445 route which is common decided to just do the .040 get new pistons, check align hone, square the decks, go for a zero piston/deck clearance, proper balancing etc

Of course the heads being a issue and did not want to spend a bunch of $$ on them silly me made the call to BBM. For not a bunch more than it would have cost to re-do the C8-H heads I had a much better upgrade!

 

out of the box the BBM heads looked great!

I ordered them with 2.15~1.68 stainless valves. With heads uncut, needing final finishing work.

 

I happened to have a boatload of different FE Alum intakes at the time but decided for this build it would be the perf RPM seeing as though the NOS Tunnel Wedge was already on another engine.

7 different FE intakes in this pic . . LOL

 

After a valve job they went to the flow bench to verify the claimed flow numbers.

In back of the '66 on each side here are 2 "extra" std std 428 cranks. Found at a garage sale!

 

Good looking heads. Will there be a big cost savings versus the assembled heads? Nice project.

 

Some for sure. The bare heads are 1350.00 and with valves but need finishing
1650.00

Completed basic heads are 2450.00 I have seen some advertised for a bit over
3000.00.

I wanted a specific valve spring combo for the custom grind cam I am using.

Here are the flow numbers . .

Intake

.200 148.4
.300 201.7
.400 250.6
.500 280.3
.600 296.4
.700 297.7

Exhaust

.200 121.5
.300 159
.400 186
.500 208
.600 219.7
.700 220.4


If I had taken the C8 heads done a bunch of port work, replaced the needed seats, new valves etc I would have had the same $$ in them if not more and it would probably have cost me 50-75 hp. A no brainer!

 

It was time to check final comp ratio numbers.

 

For the rods I used the C7's properly resized with ARP bolts.

For the small end of rod ordered undersized ID bushings from crower so by proper honing we could have all 8 rods the perfect length . .

With the decks squared and all together ended up with +.002 piston to deck.

 

For valve covers I will be using a mint set of 428 CJ's and with a little elbow grease the goal is to make them look NOS!

 

Although I knew it was good as is habit to install cam prior to crank assy to make sure all is fine.

7 M 11 dated block.

Upon install of the crank with seal and final torque it took less than 2 lb ft of torque to turn the crank. My " lb torque wrench lowest setting is 23 that easily spun the crank.

Crank end play also checked.

Also habit is to run thread chaser thru each and every hole. ARP thread compound used on all threads, same as when machine work was done.

 

It was time to find TDC and to verify the balancer markings were correct,

Made the tool for TDC back in the 80's. Always a dial indicator handy . .

Not very often the degree of cam is spot on. It was in this case.

 

Prior to start of assy I also dropped the heads in place with gaskets to see how the intake manifold fit with no intake gasket and with. Spot on! .070 from intake mating edge to mating surface of head.

I also ran a machinists straight edge across the valve stems to check. Absolutely perfect! No variance of any kind. A testament to the quality of the BBM heads and also the proper valve job.

 

I had a bucket load of FE rockers, some with very low miles. Chose the best ones along with new shafts.

Any FE person knows the rocker stands can be a bear to fit properly so I made a quick little device to hone them to perfect fit.

 

After cam was degree'd using a adjustable pushrod to determine proper pushrod length.

When Balancing assy I also did up a Auto Flex Plate so the person who buys it will have a choice of auto or manual.

Melling M57B pump was used. More $$ but pump of choice . .