[mechaniac]

I have a 454 .030 over with .100 high/10.5cc dome pistons. This is a small cam engine .459, 208/204,112. The engine currently has 045 peanut port heads. I found a set of open chamber 820 heads for a reasonable price. Not racing this or anything. Just a cruiser for fun.

Has anyone upgraded from peanut port heads to large oval ports on a mild street engine? Is it worth my time to do this upgrade? You can definately feel this engine losing power after 4500 RPMs.

 

[Harris Roc Malouda]

before head, there comes carb/intake and afterwards headers.
Those parts should be sufficient too, otherwise you just leave potential bottlenecks in place.

Before changing heads, a cam upgrade would be my first choice, to utilize the unused flow potential of the heads.
Generally a split duration cam with around +10° extra exhaust duration adresses the intake/exhaust flow discrepancy of stock heads.
A good brand is isky.
Maybe a 228/238 .553/.578 112LSA hyd roller cam with sufficient 6500rpm redline valvetrain is the hot ticket for you. Dual springs preferably for safety reasons.

speaking about heads in pure stock form in the right environment, meaning with properly chosen carb/intake/headers/camshaft and the right shortblock displacement with sufficient rev-ability, this is what i have observed:
peanut port heads should deliver 400-450 hp
oval port heads can go between 500-550hp.
rect. heads can go between 600-650 hp.
If you let a pro work on them, 800+ hp are more than possible, even with oval port heads like 781/049s.

There are countless guys with decades of experience here, keep that in mind. I'm new to the game

 

[mr 4 speed]

I have a 454 .030 over with .100 high/10.5cc dome pistons. This is a small cam engine .459, 208/204,112. The engine currently has 045 peanut port heads. I found a set of open chamber 820 heads for a reasonable price. Not racing this or anything. Just a cruiser for fun.

Has anyone upgraded from peanut port heads to large oval ports on a mild street engine? Is it worth my time to do this upgrade? You can definately feel this engine losing power after 4500 RPMs.

Couple of things here...
Never heard of 045 peanut port heads. Are you sure they aren't 049 castings which would be large ovals,not peanut port /small ovals.
Also,power falls off because of that tiny cam. 208/[email protected] .459 lift 112 LSA isn't going to exciting.
Change the cam and keep the heads.

 

[mechaniac]

They are definitely 045 peanut port heads. I’m not really interested in replacing the camshaft. The one I have is slightly more camshaft than a factory 375 horsepower 396 camshaft. I like the drivability and low end torque. I have headers and aftermarket dual plane intake. I have a factory TBI that has been worked over and bored out to 785 CFM.
I’m just curious if anyone has replaced peanut ports with large oval port heads and what kind of results they had.

 

[mr 4 speed]

They are definitely 045 peanut port heads. I’m not really interested in replacing the camshaft. The one I have is slightly more camshaft than a factory 375 horsepower 396 camshaft.

The factory 396/375 HP camshaft is [email protected] .520/.520 114 LSA
Your cam is 208/[email protected] .459 lift 112 LSA
That cam is not even close to the 396/375 HP specs.
if you want more HP and torque, lose that cam.
And, you are correct. There are 045 peanut port castings.

 

[68Chevele]

With a small cam the only thing you will notice is a loss of low speed torque going to the oval over the peanut port heads. As far as I am concerned, if knew how good peanut port heads were after a little port work, I would have never used most oval ports again as I have been so impressed with both of my sets of PP heads I ran.

 

[mechaniac]

The factory 396/375 HP camshaft is [email protected] .520/.520 114 LSA
Your cam is 208/[email protected] .459 lift 112 LSA
That cam is not even close to the 396/375 HP specs.
if you want more HP and torque, lose that cam.
And, you are correct. There are 045 peanut port castings.

Chevrolet used two different camshafts for their 375 HP 396 engine:
Solid Lifter 375 HP: PN# 3863134, 242/242 DUR, 114 LSA, 520/520 Lift
HYD Lifter 350/360/375 HP; PN# 3883986, 214/218 DUR, 115 LSA, 461/480 Lift

 

[Harris Roc Malouda]

this is some info from gm heritage center regarding L78 engines over the years:

Your current cam appears like a truck / pulling cam to me..
a dual pattern cam with intake at .50 duration in the 220s and exhaust in the 230s would be my personal choice.
another very good choice is the clay smith 229/241 cam

 

[mr 4 speed]

Chevrolet used two different camshafts for their 375 HP 396 engine:
Solid Lifter 375 HP: PN# 3863134, 242/242 DUR, 114 LSA, 520/520 Lift
HYD Lifter 350/360/375 HP; PN# 3883986, 214/218 DUR, 115 LSA, 461/480 Lift

Your cam is neither.
Change it before changing the heads.
You have a tow truck cam in there.
😊

 

[shovelrick]

Couple of things here...
Never heard of 045 peanut port heads. Are you sure they aren't 049 castings which would be large ovals,not peanut port /small ovals.
Also,power falls off because of that tiny cam. 208/[email protected] .459 lift 112 LSA isn't going to exciting.
Change the cam and keep the heads.

I have a set of “045” PP heads off the 86 Winnie 454 that used to be in my car

 

[shovelrick]

My 86 454 with 045 heads, I removed the RV cam & lifters installed a Summit/Crane 226/226 dur., .533/.533 lift 108 lsa, 3310 750 Holley on an Eddy rpm AG with 1 3/4” headers and it ran very good, swapped to 063 heads with 1.88/2.19 valves & springs to match the cam, fly cut the piston valve reliefs and it was a lot more fun, higher rpm pulling too

 

[71454Chevelle]

My 86 454 with 045 heads, I removed the RV cam & lifters installed a Summit/Crane 226/226 dur., .533/.533 lift 108 lsa, 3310 750 Holley on an Eddy rpm AG with 1 3/4” headers and it ran very good, swapped to 063 heads with 1.88/2.19 valves & springs to match the cam, fly cut the piston valve reliefs and it was a lot more fun, higher rpm pulling too

Rick, even with that small of cam you still didn't have enough P-V clearance? That combo does sound like a fun, inexpensive setup.

 

[shovelrick]

Rick, even with that small of cam you still didn't have enough P-V clearance? That combo does sound like a fun, inexpensive setup.

I might have been able to move the cam to get more clearance but I thought cutting with an Isky valve cutter was best thing to do, first machine shop didn't cut the new guides down for cam lift and I had Retainer to Guide "Clack" and I even left them the Cam Card, better machine shop redid the crappy valve job the first place did and cut the guides down IIRC .100 and I was going to use Mr Gasket steel shims with copper spray but after more measuring and didn't want to damage the ring lands by cutting too deep I bought .027 MLS gaskets, I think it ended up around 9:1 comp. and a Very snappy good running engine

 

[shovelrick]

.

 

[mechaniac]

My 86 454 with 045 heads, I removed the RV cam & lifters installed a Summit/Crane 226/226 dur., .533/.533 lift 108 lsa, 3310 750 Holley on an Eddy rpm AG with 1 3/4” headers and it ran very good, swapped to 063 heads with 1.88/2.19 valves & springs to match the cam, fly cut the piston valve reliefs and it was a lot more fun, higher rpm pulling too View attachment 764908
View attachment 764907

I am re-thinking my cam. But with my engine having dome pistons I think I am going to be confined to open chamber heads. I was considering the 820 heads becuase my understanding is that the 820s have a 113cc chamber vs the 120ish chamber of the 781/049s. I was hoping this would be an inexpensive way to bump up compression. But yeah I agree with y'all. I need to change out the RV cam.

 

[shovelrick]

You can also get Brodix Race Rites in 115cc chamber, that’s what I have in the 294 R port heads with CNC option, IIRC -22 cc dome pistons

 

[540Hotrod]

I've never heard of a 396/375 with a hydraulic cam other than the 200 Z-16's. I'd do the heads and pick a cam for them...

JIM

 

[Malibu ss 64]

Do the head swap if you stay flat tappet cam get a new from Mike Jones Cams. Both heads and cam should make a noticeable difference vs current cam heads.

Jones Cams

jonescams.com

 

[68Chevele]

Comp 282-S BBC cam is a great all around performance cam. Good Idle, great power and you can vary the lash by up to .015 on each side. I ran the best of an 11.26 with the 282-S sporting some ported peanut port heads. The 294-S works very well also but needs more compression.

 

[mechaniac]

I have never considered using mechanical lifters. What transmission and rear differential gear were you running?