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peanut port 454 1986 K30 towing

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#21 ·
For the Vortec heads (good choice) use a Fel Pro 1037 head gasket. With your stock piston (factory dish) you would have around 8.5:1 - still recommend a flattop which would give you 9:1 with those heads. because they are fast-burn chambers they tolerate are terrible pump gas just fine. If using a flat cam, go with an intake duration of around 210* @ .050" lift (I transposed numbers earlier) to 220* at the most, if a roller cam knock those down to 200* to 210* @ .050" lift. Low end torque is the objective so increasing the duration will only work against what you are trying to do. As for lobe separation, that is more of a personal choice depending on what characteristics you are looking for - wide LSA (112-114) will give you a smooth idle and a long broad torque curve, narrower LSA (108-110) will give you more low end torque and crisper throttle response, slightly rough idle, but a narrower torque curve (falls of quicker).
 
Discussion starter · #23 ·
#24 ·
Any cam upgrade in a Big Block needs upgraded springs - do not reuse stock BBC springs with anything other than the stock camshaft! The other thing you need to be aware of is the Vortec heads have rotators on both the intake and exhaust so you need 16 Rotator Eliminators - you cannot use the rotators with aftermarket springs. On the big blocks the rotators are in the head under the spring unlike small blocks where the rotators are part of the exhaust retainers.
 
Discussion starter · #25 ·
1975TypeS-3 said:
Any cam upgrade in a Big Block needs upgraded springs - do not reuse stock BBC springs with anything other than the stock camshaft! The other thing you need to be aware of is the Vortec heads have rotators on both the intake and exhaust so you need 16 Rotator Eliminators - you cannot use the rotators with aftermarket springs. On the big blocks the rotators are in the head under the spring unlike small blocks where the rotators are part of the exhaust retainers.
Click to expand...
Ah ok, I know the older ones were weak I thought maybe the vortecs would be stronger. I will plan on upgrading the springs etc.

pulled the tranny off the engine. Going to put it on the stand tomorrow. I wanted to get a bigger engine stand from Harbor Freight but none of the ones around me have the 2000lb ones in stock. I have smaller ones but wanted a beefier stand for this thing. I may just put it in a cradle for now and start pulling the accessories and the head.

But as of right now plans are

- tear down
- check bearings and cam
- try to find whatever is wrong if fixable
- buy vortec heads - Disassemble maybe send to get checked
- new cam
- flat top pistons
- hone or have bored if needed
- reassemble heads and engine

thanks everyone for taking the time with me on this.
 
#26 ·
Those L29 heads have a non-adjustable valvetrain. If you go with them, have your machine shop rework them to use conventional rocker studs so you can use easier to find and cheaper valvetrain parts. Like all production heads, they have ridges in the bowls, below the seats and on the short turns. These should all be blended in. Don't waste time trying to remove the swirl ramp, gains are minimal. I've always thought they were there for a reason of the General wouldn't have added them. I also put a very slight radius on the edges of the vane in the chamber, just to cut the sharp edge a bit since edges and points are where heat is dissipated and lead to detonation issues. With the great exhaust ports, you're on the right track in looking for a single pattern cam.
 
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Discussion starter · #27 · (Edited)
Busted Knuckles said:
Those L29 heads have a non-adjustable valvetrain. If you go with them, have your machine shop rework them to use conventional rocker studs so you can use easier to find and cheaper valvetrain parts. Like all production heads, they have ridges in the bowls, below the seats and on the short turns. These should all be blended in. Don't waste time trying to remove the swirl ramp, gains are minimal. I've always thought they were there for a reason of the General wouldn't have added them. I also put a very slight radius on the edges of the vane in the chamber, just to cut the sharp edge a bit since edges and points are where heat is dissipated and lead to detonation issues. With the great exhaust ports, you're on the right track in looking for a single pattern cam.
Click to expand...
Gotcha thanks

Got the engine on the stand and started pulling it apart. Think I have found the knock. That cylinder wasn't firing by the look of the spark plug. I guess I should have pulled plugs before but I was less concerned about the motor at the time.
 

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Discussion starter · #28 ·
Tore it down to the short block today. Only issue I have found besides the messed up cylinder was this spot of rust on the #2. Not sure what is going on here a crack in the wall?

Still have to plastigauge the bearings to see if they are ok.
 

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#29 ·
Looks like a water trail coming from the deck? probably a bad/leaking head gasket, looks like the bolt hole above goes into water...? check it out for knock but maybe it was caused by the water?
 
Discussion starter · #30 ·
shovelrick said:
Looks like a water trail coming from the deck? probably a bad/leaking head gasket, looks like the bolt hole above goes into water...? check it out for knock but maybe it was caused by the water?
Click to expand...
Yeah after posting an looking at it again it looks like a leaky gasket I think. The knock was on the other side of the engine so I dont think this did anything and it was while it was sitting not running. Hopefully it will hone out.

I am debating now not sending the block out just getting a bore gauge and checking the bores for wear and if they are decent giving it a hone and dropping in standard sized flattops. I just don't think this bottom end is wore out at just under 60k
 
Discussion starter · #32 ·
Alright bringing this back from the dead.

So after saying I didn't want to spend $1k on heads. I am well on my way. Someone is selling new l29's on ebay so I bought a pair for $850. they are the factory 19256827 ( i guess 19256821 casting #) heads off of the 8.0 crate engine. Not sure if they are take offs or what. But they come with springs but no rockers. I think they are just normal l29's and need the conversion studs but the literature says the heads are normally fully adjustable valvetrain so not sure if the rocker studs are a different size. Will test when I get them.

So looking now at pistons and cams and deciding if I want to do a roller or stick with hydraulic.

I sent an email to comp and they suggested the 11-408-8

Camshaft Type: Hydraulic Roller Tappet
RPM Range: 1000 to 5000
Intake Duration: 258
Exhaust Duration: 264
Lobe Separation: 110 °
Grind Number: XR258HR
Intake Duration (.050" Lift): 206
Exhaust Duration (.050" Lift): 212
Intake Valve Lift w/ Rocker Arm Ratio: 0.51"
Exhaust Valve Lift w/ Rocker Arm Ratio: 0.51"
MFG. Part #: 11-408-8
GTIN Code: 036584024811
External Ignition Box Required: No
Valve Springs Required: Yes


The cam in this looked interesting

xr276hr-13

Engine Family:Chevrolet GEN VI 454 and 502 c.i. 8 Cylinder (1996-1999)
RPM Operating Range:1,800-5,800
Grind Number:XR276HR-13
Cam Type:Hydraulic Roller
Lifter Style:Hydraulic Roller
Camshaft Series:Xtreme Energy Computer Controlled
Camshaft Gear Attachment:3-Bolt
Usage:Street/Performance
Valve Springs Required:Yes
Camshaft Material:Austempered Ductile Iron
California Proposition 65:WARNING: Cancer and Reproductive Harm P65Warnings.ca.gov
Advertised Intake Duration:276
Advertised Exhaust Duration:282
Intake Duration at .050 Inch Lift:224
Exhaust Duration at .050 Inch Lift:230
Intake Valve Lift:0.51
Exhaust Valve Lift:0.51
Lobe Separation:113

Maybe too much cam but seems to make solid power in the gen 6 for holdener.

Will go back through and look at peoples cam recs but open to any feedback. thanks
 
Discussion starter · #33 ·
Sticking with flat tappet maybe more inline with my budget though,

comp 11-408-8
Camshaft Type: Hydraulic Flat Tappet
Intake Duration: 268
Exhaust Duration: 276
Lobe Separation: 114 °
Grind Number: CB 268AH-14
Intake Duration (.050" Lift): 222
Exhaust Duration (.050" Lift): 226
Intake Valve Lift w/ Rocker Arm Ratio: 0.525"
Exhaust Valve Lift w/ Rocker Arm Ratio: 0.525"
MFG. Part #: 11-402-4
GTIN Code: 036584610304
External Ignition Box Required: No
Valve Springs Required: Yes

I think this maybe where I am heading. I have new flat tappet lifters in the engine and it would be nice to use them rather than paying another $100 for the cam and $400 for the roller lifters.

I have a holley 750 carb I picked up. Still need to get a manifold. Would really like to do a sniper kit on this but I think for the time being I will build it with the carb.

What springs? comp 26120?
 
#34 ·
Well I like that you are going to use the L-29 heads, I think with some work they will make some pretty decent power. Take a look at this build, the guy uses L-29 heads but the short block uses dome pistons. I though that was not possible with the newer heart shape chambers?

https://youtu.be/E83GBWQTGa0
 
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Discussion starter · #37 ·
gnicholson said:
l29 heads were never on the later 8 liter big blocks. they use cathedral port heads similiar to the ls engine. do not put a cam with 114 lsa in your engine unless you want to give up 50 plus ft lbs of torque at 2k rpm. small single pattern on 108 is what you need
Click to expand...

These heads I bought were off an industrial crate 8.0 based on the 454. Not the 8.1 that came in trucks. This guy Vortec 8.0L - Ed Rinke Performance

Gotcha on the LSA. I will look for something in the 108 range.
 
Discussion starter · #39 ·
So if I go with the top cam will it be too much lift? Sorry for all the questions. I have heard the l29's run out of flow at high lift but I think that would be within its flow range but at the upper end of what I would want to run.

Brand:Lunati
Manufacturer's Part Number:10110206
Part Type:Camshafts
Product Line:Lunati High Efficiency Camshafts
Summit Racing Part Number:LUN-10110206

UPC:788120712439
Cam Style:Hydraulic flat tappet
Basic Operating RPM Range:1,800-5,200
Intake Duration at 050 inch Lift:218
Exhaust Duration at 050 inch Lift:218
Duration at 050 inch Lift:218 int./218 exh.
Advertised Intake Duration:268
Advertised Exhaust Duration:268
Advertised Duration:268 int./268 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:0.518 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:0.518 in.
Valve Lift with Factory Rocker Arm Ratio:0.518 int./0.518 exh.
Lobe Separation (degrees):110
Computer-Controlled Compatible:Yes
Grind Number:HI-268
 
#40 ·
I went with the Clay Smith H-264-0. It is 214/214 and .500 lift on both intake and exhaust. Went with this based on their recommendation with swapping a set of the L29 heads onto my 1987 454 in my dually. They said the L29 exhaust port is so good that there wasn't a need for a split duration. It has a 110 lobe center. They ground one for me on a 112 lobe center so that it would be more compatible with my TBI. My heads are at the machine shop now getting the valve seats touched up and new springs/retainers and rotator eliminators.
 
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