I am to the point of finalizing the new combo.

Car is an '89 coupe that weighs just a tad over 3000 lbs. Tranny is the ZF, 3.54D44, and currently has a relatively strong 383.

I am looking at the following:
- Dart Little M block
- 4.125" stroke
- Oliver billet rods (6")
- JE custom pistons (18°), set at 9.5:1 scr)
- CC custom grind solid roller (250°+ duration at 0.050, 0.7 lift, 112-114LS)
- Chevrolet raised runner 18° heads with offset Jesel shaft rockers (should have the flow numbers shortly; will be over 370 cfm), Ti valves, ported by Ron's
- sheetmetal EFI intake (leaning towards Hogan's)
- Monoblade TB
- ATI D-1X supercharger (max flow is 1900 cfm, will be running somewhere around 1550, or 16 psi boost)
- F.A.S.T. for engine management

Anybody want to add some input on the combo. Thoughts on the output? Weak areas?

BTW, I will not be maintaining the L-98 type valvecovers, so ... no limitations.

Thanks,
Aaron

 

Sounds like a dang healthy motor. There are alot of common and similar parts between yours and mine - Dart Block, boillet rods, JE pistons, custom Comp solid roller with similar specs, 18* heads/Jesel valvetrain, Hogan's sheetmetal manifold, monobade TB, and FAST engine management.

Of course, your stroke is .125" longer, and if you really get 370cfm out of the heads, you'll have 15 more than mine, plus the supercharger. Sounds like alot of motor. What are you thinking? 900+hp on pump gas?

Ain't nothing weak about that combo, 'cept maybe your wallet after you pay for it all ! ;).

Only think I'd add is to get the tall deck block, which you must already be planning since you'd end up with a forced induction unfriendly .9" ish comrpssion height if you didn't! You'd be able to see though the ring lands ;). So what's it gonna be a blown 454 small block? If you don't mind running an aluminum block (and the $2000 extra), Dart makes a 9.5" deck aluminum small block. You could then run 6.125" rods, but the increase in rod/stroke ratio from 1.45 to 1.48 probably ain't worth it, unless the weight benefit is.

My only other thought - take plenty of pictures and put together a website so we can all check it out.

Good Luck!

 

Unless you are going to run it on a steady diet of race gas the compression is too high for that amount of boost. Sounds awsome good luck with it and remember to always drive carefully like I do. :D

 

Monty,
I appreciate the feedback. As for the comments on the tall deck block, I will definitely look into the aluminum block. I was looking at this in the beginning, but have backed off after some comments I had received and some things I had read. Regarding the cost, the largest expenses will be the custom intercooler and the blowewr as well as the sheetmetal intake. Most of the parts, I have already made moves to procure (either through swaps, or already have from other projects). The rods, block, possibly the crank, heads, TB fall into that category. As for the stroke and ultimate cubes, I had targeted a 447, but have considered larger with a 4.25" crank (r/s ratio becomes quite low). Though I must admit that a 454 sounds quite interesting.

Relative to comments on the cr, I do not want to fall much below the 9.5:1 mark, due to streetability concers. The D-1X will pull on the top end, but I still want to have the no/low boost driveability.

What cam were you running in your combo? CC's recommendations are above 250° duration at 0.050 with 695 lift (another option was 0.720). My heads are already set-up with the longer valves. Max rpm to CC was defined as 7000 with normal redline set at 6500 RPM. Got any thoughts around the cam? I think I want to stay at 112 LS.

HP estimates: I had estimated that my 408 (large SR cam, large heads (300+ cfm), and MRII) with the D-1 at 11-12 psi (not the D-1X) would be in the 720 RWHP. Stepping up to the D-1X and the larger cubes (447) according to ATI and CC, should yield close to 1000 hp at the flywheel (close to 900RWHP) at just average tune. I would like to see if these numbers are accurate from some of the simulators. Any takers?

Thanks,
Aaron

 

Aaron,

I don't know if you remember but I tested 4 different custom mech roller cams in my SBC 427 on the engine dyno. The cam that worked best for me was a Comp mech roller based off of theor Hi-Torque .406 lobes. It has 256/264, .690"/.650' (1.7/1.6), on a 112LSA. I was running 11.27CR, normally aspirated though, on pump gas.

My dynos are on my site, but it mage 650hp @ 6700rpm, 580 ft lbs at 5100 rpm. Before all the naysayers say that ain't a street engine, consdier that it made 425 ft lbs at 2000 rpm, and made 500+ ft lbs from 3000-7000 rpm. The motor pulls all over the rpm range, idles smoothly at 850 rpm with 13" of vacuum, cruises at 2000 rpm, and get about 20-22 miles per gallon, and it never overheats.

I owuldn't be afraid of lowering the CR to 8.5 or so, that's what I'm gonna run with the turbo setup. While it's true you lose about 4% in power for each CR point you drop, you'll be able to make alot more power by running more boost. Boost makes alot more power than CR. The 447+ ci motor will make PLENTY of torque on it's own before the SC makes boost.

Also, I don't think you need to run so much lift with a forced induction application. My turbo cam is going to be much closer to .600 than I'm currently running. Even with the best springs, so much lift is still a killer in the long run. Of course if you don't mind changing springs annually like me, go for it.

My only real adivce, beside good luck and drive safe ;), is to grow some thick skin. 95%+ of the people will tell you it can't be done, it's crazy/stupid, it'll never be streetable/drivable, it won't be a street car, etc. I've been hearing it for years. Do you homework, which I know you already have, and have fun.

 

Monty,
I snapped some shots of the heads tonight. I will try to post them shortly. The valves are Ti with 2.15"I, 1.625"E. The Jesel shaft rockers are offset with 1.65I/1.60E. Heads are awesome. The guy who operates the flowbench said to expect numbers that exceed the 370cfm mark. We will find out. They have lots of epoxy and porting done. One of the nice things is that all the heads that are done by Ron's are serialized, so you can find the history of the work performed (or were they ever "train wrecked"). I have them looking up two sets for the history/flow numbers. I will compare these values with what I get on the local flow bench. What size are your runners (intake and exhaust)? These seem like they must be like 240-250cc, while the combustion chamber looks to be like 50cc. I'm just guessing at this point.

I will again research the cam with CC. It seemed in line with what I am running in my 408 (0.640 lift). I will talk to them again.

As for the naysayers, I have heard many of the comments with regard to my 350 with the blower, the L-98 block with 4" stroke, running the SR cam that I run on the street, converting an '87 over to the ZF tranny, ect, ect. I like being different. I think that most people that know me, know that that is what pushes me on. These same people know that I push out first rate cars/combos. Example is the comments with regard to my posts of the 408 engine pics in C4 Tech.

Anyways, as always, I appreciate the assistance from the tech end from you and others on the forum. Give me some feedback on the Hogan manifold. I wonder if this unit would bolt up direct. What was the cost? I am having great difficulty getting them to deal on a price for a single intake. Thoughts?

Thanks again,
Aaron


[Modified by AKS Racing, 6:38 PM 12/11/2001]

 

There's no doubt, Hogan's ain't cheap. My manifold was $2400 which is their price for an EFI manifold with single TB, including fuel rails.

Every manifold is custom made. I requested a catalog and told them I wabted a manifold for 18* heads. They sent me a form which I had to provide all the measurements on - head port size, port locations, deck height, etc. Even with the tall-deck block, whioch spreads the heads further apart, their custom manifold fit perfectly. Their manifolds are beautiful. You seem like the kind of guy who appreciates excellent craftsmanship - it's almost a shame to hide it under a hood. It comes already ported inside, ready to bolt on. The only thing I would suggest is to add another vcuum port to it. It only came with the IAT bung and one vacuum port on it. I had my machine shop put another bung in it for the IAT sensor in the bottom of the plenum, and used the original IAT bung for the power brake connection. The other vacuum port is used for the fuel pressure and MAP sensor vacuum connection. Also, you will need to use an MSD Pro billet distributor with the small diameter cap. If you go with a sequential Speedpro ECM, you'll have to remove all the reluctors except for one from the distributor. This is what the SEFI unit uses as a cam position indicator.