As the title states, has anyone built a 15° or 18° headed motor for their C4? Did it live to your expectations? Lessons learned? Would you do it again?

Considering an SB2.2 combo on boost. I had thought that RainDelay had a 18° Bowtie head set-up in his C4?

Any and all comments welcome.
Aaron

 

I know its been done. I think the guy with the 434 C4 video on youtube was 18 degree heads...thus the reason he ditched the mini ram.

 

Steve (RainDelay) did have 18 degree heads on his 434 and I'm sorry to report, that THIS particular motor is no longer with us. He believes that it had everything to do with the level of detail and precision that went into his short block assembly. Steve has just started a new job and I haven't seen him in the past few weeks, but as SOON as I catch up with him, I'll tell him to get back here and make comments and update us with his motor status! The last word from him was a $5,700.00 repair bill to fix the 434, and his decision to not take that option with that particular shop!

R/Noland

 

Thanks for the comments.

I had communicated with RainDelay as he built the large cube 18° combo, as I had previously done an 18° head engine. I lost track of him right at the end of his build. What exactly went awry with his engine?

I would like to do a smaller cube 410-420cid SB2.2 engine with large boost, and was looking to see if others had comments.

The way I look at it is this:
- NASCAR guys were getting in excess of 800HP NA by spinning to 9000RPM
- take the basic set-up and tone it down, but increase longevity through SR cam, and lower RPM
- add tuneability through individual port FI
- add power through more cubes (410-420 cid)
- make 750+ HP NA, then add a large amount of boost (keep in mind that boost just improves upon what was available NA).

Put it all in a killer C4 race platform (i.e. full cage solid axle car), and have a great track car (one that will actually 60 ft better than 1.75 sec) and still be a "nasty" street car.

I like building engines, and I have the top end already available, as well as the "boost-maker" and a chassis that one could go wild in caging.
Aaron

 

what happened to his stroker motor before the 434? i missed about a year and 1/2, havent seen steve or jerkey boy(dave) since i got back on.

 

jerky boy is around...going thru some tuning issues right now I believe.

 

Was steve (raindelay) the one with the silver 85?

 

Not in a C4 - but I have built MANY 15 and 18 degree SBC's. Both are a different world as compared to the SB2.2 engine (which I've built a few of in the past 6-7 years).

What's your expectation? 750HP before boost? Its going to take some real compression and race gas to make that with any of these heads.

I've made well over 800HP normally aspriated, using Brodix -12 (15 degree) heads. They are a very strong and well thought out casting. They use common 18 degree valve train parts and the smaller port versions work well on small (4") bore engines (the HVH desgined 247cc port) . Honestly -12's can make over 700hp normally aspriated by anyone in their garage buying parts on line or over a phone tech line. They are also very cheap as compared to some other options. Some older Weld Tech CNC ported heads are availiable for about $3195.00 (complete) that will make all the HP you need depending on what bore and stroke you plan to run.

There are a bunch of junky GM 18 degree heads out there. Most of them are worn out 9.1 Bush GN and Truck series stuff. Crap its hard to believe some of those heads are like 15yrs old now... Anyway there are some real good ones out there too, but most people who have a set arn't selling. The only thing is if a set of GM 18 degrees came up for sale, could YOU tell the difference?? Eldebrock, Brodix, All Pro and TFS offer 18 degree heads as well that range from OK to Awesome if you buy new and take them to a good porter...

Some of those NASCAR take off 2.2 heads are pretty thin is places and I don't know how long they would live on a turbo. I will also tell you the port CSA's aren't even close to being optimised for forced induction. A few other tech notes on them. The SB2.2 has a lot of pushrod angle when you put them on a regular SBC block. You must run the 18 degree .180 offset roller lifters. It hasn't caused me any problems on our oval track engines but it's not the best RE-desgin I've ever seen either (it is cost effective thou). If you do go this route (SB2.2 on SBC Block) DO NOT use those dual offset lifters as it will certianly break the lifter tie bar with continued running on the street. None of this is an issue if you buy a P/N 24502600 SB2 block and use solid lifters like the NASCAR boys do but that block is not really optimised for long stroke cranks (and is not cost effective).

There are a million little things about these engines I can tell you but I'm not going to try and type it all out here without knowing what your final expectations are. I couldn't remember everything about the differences between all of them (in one sitting) anyway. If I could, it would eat up a few pages of bandwidth.

Will

 

I buddy of mine bought a set of 15* Brodix heads for his 434 too. Engine went in a 86 Vette. They were close to being a night-mare to configure correctly.

Valve train geometry called for special off-set lifters and he went with a Jesel shaft rocker arm setup that called for lots of tweaking. Even after that, the custom made pushrods from Smith Bros (I believe that's who made them for us) sat an an angle I was never happy with.

The Mini-Ram had to be welded up a couple of different times in order for the water ports in the heads to be covered and to make it properly fit the heads.

The Mini-Ram had to be cut open, ported, then welded back together several times to elimiate turbulance which restricted air flow. The porter in CA was finally able to get the Ram to flow close to 400 CFM, but it took a LOT of work. Guy use to port and flow for Extrude Hone, so he knew his stuff.

Custom built headers were needed too.

My opinion: They called for a lot more work than they're worth.

Jake

 

Will,
Thanks for the detailed response.

Let's start with what I want...
I have built many different FI applications (S/C and T/C). I have had so many different S/C'ers in my own vettes, that I would like to do something new. My current combo made ~480WHP NA and can make rediculous power when you add big boost.

I would like to increase the NA power level by 150-200WHP and then add boost on top of that. I have a complete 18° matched set-up (head, Jesel shaft-rockers, intake, vc's, SS headers, etc.) from Petty Enterprises. I also have access to similar SB2.2 parts from another major competitor, so either route may be available. I would like to stay with either a stock type block, or one of the more common World or Dart products with new top-end. I would also like to stay in the 410-420cid range and add power through boost. I have built considerably larger engines, but feel this is a more reliable route.

Basically, nothing from any of my current cars would transfer to the new build, so I may as well start from scratch. Plus I have a lot of parts sitting around.

I am all ears to any suggestions that you might have.

Thanks,
Aaron

 

I've been down this road on my last combo, so no need to do that again. I will be using a SP intake converted to fuel injection. The SS stepped headers that I currently have will need to be rebuilt or "re-created" completely.
Aaron

 

He still has the 408ci block at the house, and his last converstation with me and Will, was that he was going to put that back in the Vette until he could figure out what he wants to do with the 434. I think right now he's weighing all of his options at this point, but still has the 408 which will keep him on the road and a viable backup.

Yep, I think it's an 85 and it is a Silver Coupe.

 

yes, I am the one with this motor. Yes I would do it again!! the long block was no problem, Jake did an excellent job of building the engine!! As he mentioned the Mini Ram intake was a problem to mate up to the heads. The problem with the valvetrain was that, the push rod angles look liked a big block. since the bowtie block had the taller lifter bores, it limited the choice of offset lifter that I could use to straigten out the pushrod angle. After all that what I thought need to be fixed was perfectly fine according to Dennis Wells. He showed me a couple of his 18 and 15 degree engines and the rod angles are shifted.

The cam is 250 / 256 on a 106 installed 4 degree advance, it basically a low compression sprint car combination. It idles at 850 rpm, I drove it once before the current tune. It scared me in a good way. There were transmission cooling is being upgraded. This motor was built for topend and the current coolers location needs to be changed.

 

If a guy didn't already have half the parts, it almost sounds like one would be better off with some form of LS1 swap (LSX block/LS7 heads?).

 

The first thing I see is you want to build a big motor (over 400 inches). You have an 18 degree topend thats already been sorted. Considering your goals and the added difficulty and expense of putting SB2 stuff on a SBC block, I think the 18 degree stuff is a better route for you.

Since you already have the rockers and stands from a running engine, hopefully you don't have to worry about that stuff. T&D and Jessel rockerrs can be a PITA to set up properly if you don't do them all the time. You will need to buy some .180 offset lifters. The ISKY's with forced pin oiling are about the most reliable ones I've ever used with modern engines. Try to stay away from getting a block that has the camshaft raised. Great for rod clearance but as others have found it makes pushrod angles a scary looking nightmare.

Now as far as HP. Petty went thru a few different people and companies with heads back then. None of them were the best but I do know a Super Late Model guy in GA that bought a bunch of Pettys 18 degree stuff about 8-9 yrs ago and had well know local area engine builder (Lamar Hunt) build him some short blocks for it. One was a 358 inch motor that ended up making 720HP. It was 14.1 SCR and it turned about 8000RPM every night. So I know the potential some of that stuff they sold of has. Those heads and cam (270's@.050) would make peak HP some where around 68-7200rpm in a big motor and make about the same peak HP but a crap load more TQ/HP below the peak.

I figure a loss of compression (down to 9.1) and pump gas would kill 100-150HP right off the top. So about 560-620HP NA on pump gas. The 18 degree chamber is pretty efficient and we never really got any detonation problems out of those old 9.1 Bush motors and we ran them so lean to make HP (the egts were so hot) they would burn stainless headers up after 1 race. BTW orginal 9.1 Bush or Truck heads will have 5/16 stem Intake valves and 11/32 stem exhaust valves because the exhaust heat was so bad. The combustion chamber will also be about 60cc instead of 40cc making it a lot easier for you to make a good street engine out oft them.

I'll be the first to tell you, I don't know crap about racing serious turbos or super chargers. So I don't know how much HP you could add back at 9.1SCR. It would be hard to get any lower because of the big bore and stroke your going to have to have to make your cubic inch goal.
Will

 

If he didn't have all the parts.

 

Oh I'm still around trolling. I am thinking about pulling the motor this winter and re-doing it. I have had tuning issues but I think the build was not as well done as it should have been. My miniram doesn't fit well and not matched to the heads. The Brodix heads are pretty good for 23* heads from what I am told so I'll probably keep them but I am looking for other ideas to get me over 500rwhp N/A. I should be there with my combo but it ain't happening and I have so much blow by now that I can't afford the oil usage

I haven't spoken to steve (Rain Delay) in a while. I went to see him just after he put the 434 in the car. Nice looking piece. Sorry to hear it didn't work out. Sounds like the same issues I've had I'll be watching all of your all's builds.

 

The 18° heads that I have are the smaller (I thought 46cc heads, but you may be right at 40cc). Would you like some pics to get the discussion started? I have a lot of the other components (lifters, etc), but I do not think they will do me much good.

I believe that I can use the 18° heads with a factory L-98 block, or a WP or Dart block? Obviously not a raised cam block, but still able to get the cubes.

I wonder what I would pick up in a similar 4" stroke build like I run now? I dyno'ed at ~480WHP on a Mustang dyno NA, so how much could I realistically pick up with similar build. Current components are 4" Callais crank, 5.875 Oliver billets, JE custom, L-98 block with lots of work (splayed caps, i/2 fill, restrictors, oil stacks in lifter galley), SR 248/254@0.050, 0.67x lift, AFR 210CPs with more work 322CFM @ 0.650, Jesel shafts, Weiand Team G Single plane, MB, FAST sequential. The power adder adds a whole new dimension to the power equation, so lets keep the discussion simple by focusing on NA, then I can worry about the boost later. If I could pull the NA number closer to 600WHP on a Mustang dyno, I might go for another 408, but a few more cubes would be nice...

Focus on 9.3-9.4:1 SCR.

Thanks for all of the help.
Aaron

 

Lets see them. Kinda hard to tell anything about a port in pics thou.


An L98 block is only going to bore 4.060 max. You could only make a 414 inch motor with it (4.060X4.00). Added to the fact that depending on what bore and stroke combo Petty was using at the time - your heads may not be configured for a small 4" bore.

The early "low port" 352 casting and the later "high port" 364 castings have the best chance of being configured for a small bore (both share a 1.935 Intake valve centerline and the combustion chamber centerline in releation to the bore centerline is only offset by .805).
The 364 Castings were great restrictor plate heads and some teams like to run small bore motors in the restrictor plate motors back then (for a very short time as eventually big bore short stroke won out even in the restricted engines).
The "high port" 363 castings were pretty much all big bore stuff (1.955 Intake valve centerline). GM even recommended a min bore of 4.060 (because GM change the combustion chamber centerline offset to .825 in releation to the bore centerline) but once they left GM teams did all kinds of stuff to change them even further.

Now this is nice to know info about 18 degree heads but you need to know that Petty was always cheap... let me re-phrase that. VERY FRICKEN CHEAP with their engine stuff and who knows if they didn't take some of these heads and re-configure the combustion chambers later for a big (4.100+) bore. Easy way to tell is to take a caliper and measure across the combustion chamber at it's widest point (which is usually adjacent the intake valve to adjacent the exhaust valve). If it measures like 4.080 or smaller it's a small bore config. If it's bigger (like 4.165) it's a big bore config.

Depending on what you get for measurements and casting numbers should help you decide which block to use. Once you have that info we can figure out how hard its going to be to make your target SCR and HP goals.

Anytime.
Will

 

I have thought about the ideas of an 18* or better motor for my car as well. However I keep coming back to the point that where I am at now is it would be minimal gains for the money spent to get another 100 hp.

You would be challenged by intake, converter stall speed and headers primarily. The intake and headers will be a nightmare unless your pretty savy in the fabrication department. Also if you want to run the car on the street you are going to be really limited with the longevity of things and premium fuel ( if you are going this far, I will assume you will take advantage of the gains from compression). With these heads the RPM range is usually pretty far up and thus you will need a pretty steep converter to take advantage of the power. Right now i have a 4800-5200 stall converter. More heads will need even more stall.

Where I always come back to is right now with a 434 on 23* heads and running low 10s in any weather is the money spent on more power from another motor is hard to justify. Nitrous would be the next move if more power was needed and I can still maintain the streetability.

Lastly, more power than a solid 434 with good 23* heads on the street is complete overkill. I have had a few close calls not even screwing around on the street with my car where one second your gradually accelerating at 40-60mph and the next second the rear tires are up in smoke and your heading for the guardrails. I could not imagine another 100-200hp!

Keep us posted on your buildup if you opt to go the 18* or better route. If you do I can put you in contact with a head guru that will give you an 18* head that flows at or over 400CFM!