[b-man]

Originally Posted by mgarblik

If you end up with KRE heads , be advised you will need to helicoil all the fastener holes. For some reason, they don't use them at all in any location. I do the intake and exhaust manifold holes, rocker arm studs, valve cover rail and the front accessory attachment holes. Other than that, they are nice heads.

That’s a bunch of work/expense tapping for all of those different sizes of Heli-Coils and installing inserts.

One wonders why they don’t offer that as an extra cost option. It wouldn’t really cost them much more to just use the correct insert taps and then tap all the holes for inserts on the CNC during the machining process. Then give you the option of having them install the inserts or let you handle it.

[SD455DJ]

I just paid $1213 for a complete rebuild of my #12 heads...clean & mag heads, resurfacing deck and exhaust surfaces, install brass liners, cut for seals, hi-perf street valve job, new Ferrea 1-pc SS valves (16), new CC dual valve springs, retainers, & locks, two separate washes, and assembly at a very competent shop. This price includes 6% sales tax too.

Dennis

[steve25]

That sounds far more like it !

That Butler price of 2300 includes the iron heads not just rebuilding a set.

[rjpaige3]

It seems like the stock engine already hits your targets. Since you have the 5 speed overdrive, why not just put in new rear gears? At least 4.11, maybe even 4.56.

[spawn_x]

Originally Posted by mgarblik

If you end up with KRE heads , be advised you will need to helicoil all the fastener holes. For some reason, they don't use them at all in any location. I do the intake and exhaust manifold holes, rocker arm studs, valve cover rail and the front accessory attachment holes. Other than that, they are nice heads.

What is the issue with fastner holes?? I cant say Ive heard this mentioned. Not a small project.

Thanks for the lwad on the 6x heads

[spawn_x]

Originally Posted by rjpaige3

It seems like the stock engine already hits your targets. Since you have the 5 speed overdrive, why not just put in new rear gears? At least 4.11, maybe even 4.56.

I put OD not to be at crazy high rpm on the highway, gear like that would put me back up there ??

I do wish I went with the 3.27/.72 version tho, for anyone considering the tkx.

[b-man]

I had a friend with a 455 powered 1965 GTO convertible. He had a 200-4R transmission in it with a 4.11 rear end.

First gear was useless, couldn’t get traction.

After switching to a 3.08 rear end gear the car was much more driveable and enjoyable.

[78w72]

Originally Posted by steve25

That sounds far more like it !

That Butler price of 2300 includes the iron heads not just rebuilding a set.

Still seems priced extremely high... so if a good 3 angle head rebuild is $1000-1300, that still means they are charging $1000 for a set of iron 6x-8 heads. No thanks. For a few hundred dollars more you can buy an assembled pair of edelbrock D port aluminum heads from summit.

[mgarblik]

Originally Posted by spawn_x

What is the issue with fastner holes?? I cant say Ive heard this mentioned. Not a small project.

Thanks for the lwad on the 6x heads

There is not a direct issue with any of the fastener holes. However, if running spring pressures over 150 lbs. on the seat and 300 Lbs open, pulling aluminum stud threads out is pretty common. When using stainless steel fasteners such as ARP, the bolts will often gall and pull out of the intake/exhaust/accessory bolt holes. Using a liberal coating of anti-sieze will help some. When fitting headers, it is common to have a little trouble starting some of the bolts. Aluminum threads are much easier to cross thread or strip than a heli-coil. Accessory bolt holes tend to pull out over time with all the load on the brackets going into aluminum threads and heads. When spending over $2000.00 for a set of heads, it would be a nice touch to have fastener holes that can hold up to several installations/removals without everything being stripped out. It's just part of making a quality product IMO. I like the KRE heads, but feel this wasn't the best place to cut corners. Even the cheapest of the cheap Speedmaster heads have some heli-coils factory installed. (rocker stud and exhaust holes).

[mgarblik]

Originally Posted by SD455DJ

I just paid $1213 for a complete rebuild of my #12 heads...clean & mag heads, resurfacing deck and exhaust surfaces, install brass liners, cut for seals, hi-perf street valve job, new Ferrea 1-pc SS valves (16), new CC dual valve springs, retainers, & locks, two separate washes, and assembly at a very competent shop. This price includes 6% sales tax too.

Dennis

My quick math of typical parts prices comes up with right at $700.00 worth of parts alone! That's at discounted Summit type prices. If they are doing all that shop work for only $500.00, their shop labor rate must be about $75.00 an hour. That's one heck of a deal. No idea how they stay in business at that rate in this economy. Around here, the parts and work you describe would be at least $1600.00-1800.00.

[JLMounce]

While I do think helicoils would be nice. I want to point out that my experience with the KRE D-ports has not suffered by not having helicoiled fastener holes.

I've had the heads for 10 years at this point and haven't had a single issue at all with the heads as supplied by KRE. Spring pressures around 145 on the seat.

[SD455DJ]

Originally Posted by mgarblik

My quick math of typical parts prices comes up with right at $700.00 worth of parts alone! That's at discounted Summit type prices. If they are doing all that shop work for only $500.00, their shop labor rate must be about $75.00 an hour. That's one heck of a deal. No idea how they stay in business at that rate in this economy. Around here, the parts and work you describe would be at least $1600.00-1800.00.

Mike, parts were $522, labor at $691.

Dennis

[mgarblik]

Originally Posted by SD455DJ

Mike, parts were $522, labor at $691.

Dennis

Smoking deal on the parts, and a very good deal on the labor. I am a warehouse distributor for Ferrea and I can't buy that stuff for those prices!! Fantastic!

[android 211]

My .030" over 455 with 068 cam, '96' heads, 1.6 rockers, Rochester, 1 5/8" headers, cast iron intake, turbo 400 and 2.73 rear is a lot of fun to drive and gets about 12 mpg cruising at 67-70 with the air conditioning on. It also pings a lot on 93. I'm still dialing it in and need to play with the timing and add some sort of cold air system too. The idle is super smooth and I think I could of gone bigger in the cam department.

[grivera]

Paul (GTOFreek) has previously advised on here of the threads pulling out on KRE heads.

[android 211]

Oh and the my combo made 367hp and 524 torque. The power plateaued at 4400 and began gradually falling off after 4500. The torque was 524 at the beginning of the pull at 3000 and gradually fell off gradually.

[spawn_x]

Originally Posted by mgarblik

There is not a direct issue with any of the fastener holes. However, if running spring pressures over 150 lbs. on the seat and 300 Lbs open, pulling aluminum stud threads out is pretty common. When using stainless steel fasteners such as ARP, the bolts will often gall and pull out of the intake/exhaust/accessory bolt holes. Using a liberal coating of anti-sieze will help some. When fitting headers, it is common to have a little trouble starting some of the bolts. Aluminum threads are much easier to cross thread or strip than a heli-coil. Accessory bolt holes tend to pull out over time with all the load on the brackets going into aluminum threads and heads. When spending over $2000.00 for a set of heads, it would be a nice touch to have fastener holes that can hold up to several installations/removals without everything being stripped out. It's just part of making a quality product IMO. I like the KRE heads, but feel this wasn't the best place to cut corners. Even the cheapest of the cheap Speedmaster heads have some heli-coils factory installed. (rocker stud and exhaust holes).

great info!!!

[EksCelle]

I daily drive a Bonneville with a 455. Heavier than your GP, but close. This car tickles 4,000 RPM maybe once or twice a week thanks to the super tall gears in the back. I think I should chime in.

I put a Comp XE cam in it when I built it 4-5 years ago and I hated it. Switched to a Summit 2802 and it's been a blast. Good idle vacuum, runs the A/C just fine, and the TH400 doesn't complain too much. With a manual it would be perfect, maybe with some 3.23 gears for a nice cruising RPM. I get about 11-12 MPG with the A/C on with 87 octane.

There's users in this thread that are a lot smarter than me that can give you a better opinion, but I'm really not sure aluminum heads are what you want for what you're going to use this car for. For a street car on 89 octane, aluminum heads are total overkill IMO. You're not trying to win any races, 4x heads are great. Keep the CR around 8.5:1 and the 2802 will love it. Definitely start asking around some machine shops near you for some prices to get those heads worked on, you might be surprised. I may be biased but I find it a lot more satisfying to keep old iron in use than replacing it.

[SD455DJ]

I have to agree that you don’t need aluminum heads to make good low-end power with a 455…and keep it affordable. You can get great power from the cheap and readily available 6X-8 heads. As mentioned previously, you need more cam, like the Summit 2802 at a minimum. The only place a factory 067 cam makes more power than a 2802 is from idle to 1500 rpm.

Here’s an actual dyno comparison of two 455’s using the same short block and cam (Summit 2802 & lifters) with different top ends…the first is with the original 1970 small valve 455 #15 heads and log manifolds (the standard 1970 Bonneville engine 360hp/500 lb-ft). The untouched #15 small valve heads had 90 cc’s finished (9.94 to 1 compression) with 195/145 cfm approximate flow. It dyno’d at 390 hp at 4600 rpm and 512 lb-ft torque at 3400 rpm.

I later switched over to ’71 455HO heads/intake/carb/RA exhaust manifolds. The 455HO #197 heads were also untouched originals with 108 cc chambers finished (8.60 to 1 compression) with 225/175 cfm port runner flow. I was surprised it made a bunch more power with a 1.4 drop in compression, but better flowing heads and exhaust. It made 431 hp at 5000 rpm and 535 lb-ft torque at 3500 rpm. It made a little more torque down low than with the small valve higher compression heads. Both combinations had the Felpro 1016 head gaskets (0.039” crushed thickness) to provide 0.040” quench.

The same engine with stock 6X-8 heads (more common and cheaper than the 6X-4 heads) would wind up somewhere in between power-wise, or around 410 hp at 4800 rpm and 525 lb-ft torque at 3500 rpm. The 6X-8’s have 100-102 cc chambers uncut, and after a truing cut gets them down to 98-99 cc’s netting roughly 9.25 to 1 compression on a 455 that is zero-decked.

Dennis

[jhein]

The way I would approach the question regarding the cam is to ask what is the biggest cam I could use and not need a stall converter. Maybe that's what you have now, maybe a little bigger, I don't know. Seems like a cam such as that would also have plenty of vacuum and would given you the best possible mid range power.