Anything inherently wrong with this BBC combo?

[Jim2527]

492? .030 over. Flat top pistons, Comp K kit K11-413-8, Edelbrock dual plane intake, Holley carb, long tube headers. Stock 781 heads with stainless undercut valves. nothing exotic....

'82 chevy pickup, Muncie SM465 with the low 6.55 first gear.

XR264-HR cam
Advertised Intake Duration:264
Advertised Exhaust Duration:270
Intake Duration at .050 Inch Lift:212
Exhaust Duration at .050 Inch Lift:218
Intake Valve Lift:0.51
Exhaust Valve Lift:0.51
Lobe Separation:110

Is there anything glaringly wrong with this combo? Its just for cruising around.....

[mag2555]

The only think that comes into my mind is the likely high cylinder pressure that could be made by that Cam that is too me too small for that amount of cid.

[mt-engines]

492? .030 over. Flat top pistons, Comp K kit K11-413-8, Edelbrock dual plane intake, Holley carb, long tube headers. Stock 781 heads with stainless undercut valves. nothing exotic....

'82 chevy pickup, Muncie SM465 with the low 6.55 first gear.

XR264-HR cam
Advertised Intake Duration:264
Advertised Exhaust Duration:270
Intake Duration at .050 Inch Lift:212
Exhaust Duration at .050 Inch Lift:218
Intake Valve Lift:0.51
Exhaust Valve Lift:0.51
Lobe Separation:110

Is there anything glaringly wrong with this combo? Its just for cruising around.....

I'd say the flat tops should be a small dome and the cam needs 15 more degrees of duration

[mt-engines]

The only think that comes into my mind is the likely high cylinder pressure that could be made by that Cam that is too me too small for that amount of cid.

if you cant fill the cylinder, it wont have much cylinder pressure.

[FC-Pilot]

When you say “cruising around” what does that mean? Local car cruise? Burger joint car show? Daily driver? Hook to a trailer every now and again?

I ask these questions as the use is a little vague. Flat tops on a 4.25 stroke can be anywhere from dismal to north of 9 to 1. I would guess around 8.3 to 1. (That is a very rough guess). If so I would deck the heads to get them close to 9 to 1. If just as a weekend cruiser to the burger shop I would go with that. You have no expected time slip to match so it would be fine and drive smoothly. Are you giving up power? Yes. Are you ok with that? That is for you to answer.

Paul

[Jim2527]

If the flat tops are replaced with a 20cc dome with this kit >>> https://www.skipwhiteperformance.com/ca ... rms_92553/ and the 781's are milled to a 117cc chamber, what do you guy think now?

Truck is driven almost daily weather permitting.

I calculate static CR at 10.19 with a 4.28 bore, 4.25 stroke, 4.37 head gasket bore, .039 thickness, 117cc chamber, 20cc dome piston, .010 piston deck clearance.

Thanks!

[pdq67]

10 to 1 CR, I would back it off to like 9.5 to 1 and install no more than a CC 282S solid cam in her.

I have one in my 496 that is right at 9.5 to 1.

I figure that you will be very happy with one..

pdq67

[1980RS]

492? .030 over. Flat top pistons, Comp K kit K11-413-8, Edelbrock dual plane intake, Holley carb, long tube headers. Stock 781 heads with stainless undercut valves. nothing exotic....

'82 chevy pickup, Muncie SM465 with the low 6.55 first gear.

XR264-HR cam
Advertised Intake Duration:264
Advertised Exhaust Duration:270
Intake Duration at .050 Inch Lift:212
Exhaust Duration at .050 Inch Lift:218
Intake Valve Lift:0.51
Exhaust Valve Lift:0.51
Lobe Separation:110

Is there anything glaringly wrong with this combo? Its just for cruising around.....

It will make a ton of torque. I would run a little more cam but what you picked out should work fine. Just be aware of the huge gear drop between 1st and 2nd otherwise it will be a fun truck. I had a K5 Blazer with that trans years ago and it would out pull most performance cars in it day back in the mid 80's.

[ProPower engines]

If the flat tops are replaced with a 20cc dome with this kit >>> https://www.skipwhiteperformance.com/ca ... rms_92553/ and the 781's are milled to a 117cc chamber, what do you guy think now?

Truck is driven almost daily weather permitting.

I calculate static CR at 10.19 with a 4.28 bore, 4.25 stroke, 4.37 head gasket bore, .039 thickness, 117cc chamber, 20cc dome piston, .010 piston deck clearance.

Thanks!

Regardless that can be a lot of milling to be at 117 cc's. Then the intake fit needs to be corrected.
Why not just use the correct dome for the heads you want to use??? Less costly and less work overall.
Pistons will be the same cost depending on brand. Just remember those kits that use wiseco pistons are private label orders.
They do not always come with the best ring. They just come with a cheap basic Hastings ring. Nothing special.
Seen lots of their kits from guy here and there is always something else to buy later...........like the right bearings.
They always provide std bearings and you will not know till the block and crank are together in front of you what you will need for proper clearance with out accepting way too much oil clearance with aluminum std size bearings.

You can order kits from them without bearings and rings unless you are getting Mahle pistons and even then they only have a drop in ring set not file fitted ring sets unless up grading the kit again extra cost.

JMO