A few forum members have been asking about the status of my latest engine buildup, so here is an update w/ some pictures. For review, my previous setup made 566 RWHP and 563 RWT on pump gas. Depending upon actual driveline and accessory losses, this equates to 670 - 700 flywheel HP. It ran very well in this configuration, but I got "the bug" again and decided to step up. My goals are to add another 75-100 HP through more compression, better heads and more aggressive valve timing, yet still remain streetable and operate on pump gas.
Here is a comparison of the old vs new combination:
Displacement: Old = 540 New = 548 (.030" overbore)
CR: Old = 10.35:1 New = 11:1
Heads: Old = Brodix-2 New = AFR 335 CNC
Intake: Old = Holley Strip Dominator New = Edelbrock Victor Jr
.050" Valve timing: Old = 254/260 New = 266/272
Valve lift: Old = .661"/.668" New = .717"/.687"
Some additional changes, although done for reliability rather than horsepower, include the use of coated main, rod and cam bearings. The lifter bores have been indexed and bushed, and I will run Crower Severe Duty roller lifters w/ High Pressure Pin Oiling (HIPPO) option.
I completed assembly of the 548 short block about 1 month ago. I'll paint it next spring after it warms up.
The heads are the new AFR CNC 335 heads, angle milled to yield a 110cc combustion chamber volume. I believe these are among the best available standard port BBC heads on the market today. They offer great flow with a moderate port volume.
The Edelbrock Vic Jr intake manifold will not fit under the factory 67 big block hood. I wanted to retain the stock hood as a completely stock exterior is important. Bernard Mondello did the porting on the intake, and milled an angle on the carb pad to match that of my previous Holley Strip Dominator intake. Bernard does excellent work as you can see in the attached pictures. The small amount of epoxy in the floor of the intake runners is blended so well that I cannot tell by touch where epoxy ends and aluminum begins. Even the texture matches that of the surrounding aluminum.
I'm holding off final assembly of the engine as I plan to send the heads to Stahl Headers for header fabrication. The AFR head uses an exhaust port raised .375" and Stahl offers std port and raised port (0.6") BBC Corvette side pipe headers. After speaking w/ Judy Stahl, she suggested I send the heads for better fitting. These headers will be 2 1/8" primaries w/ 3 1/2" collectors. They will ultimately feed 3 1/2" pipes in the factory side pipe covers and I will use oval Borla XR1 3 1/2" in/out mufflers.
Unexpected expenses unrelated to this project will delay further purchases (headers, mufflers, exhaust pipes and chrome turnouts) until spring '04 when finances are more favorable.
Any other engine buildups in progress out there? I'd be very interested to learn about some of your engine projects.
Actually it's a *three* piece timing chain cover! This will allow for cam phase adjustments without dropping the pan or removing the damper. I'll only have to remove the water pump.
I use a Stewart Stage 2 short water pump. Comp supplies button head screws w/ the 3-piece cover that will clear the short Corvette water pump.
I did have to modify the Tavia timing pointer to clear the new cover, and I also had to shorten the supplied timing cover bolts. Sometimes the aftermarket is a little lacking in attention to detail....
I look forward to being able to record new sound files!
I need a timing cover like your three piece for my 427 SBC. I've also just started to consider a quiet type gear drive just because I have not had one before. I don't want to put the money into it of the belt drive since it's a wimpy 242/248 h-roller.
As I remember your old sound download was when you had the 4.11 rearend. I don't think you were in any of the gears mor than a second or two
till red line 5th at 130 mph or what ever it was. Kind of like a 10.40 @ 130 mph.
Jim told me that it was bad to the bone when he drove it :thumbs:
If you guys want to know one of the secrets of AFR BBC heads, look closely at the intake port. Check out that radius deep in the port on the inside wall down where the short turn radius is. They really raise that side of port to angle flow correctly into the port. Rather than just chasing flow bench numbers alone, they spent time figuring out what it really needed to get air into the cylinder with a piston in the way. This help direct flow into center of cylinder away from wall.
It's going to be fun to see how this monster does. It was killer before...this is going to be unreal!
Looking good Mark! What size dome did you need to get to 11:1, and what deck height are you running? That intake looks awesome! Makes me want an L-88 hood.
How do you handle your coolant temp sensor? Intake or heads? I may have to drill and tap my new heads for the guage sensor, and the Spal fan sensor.
I'm on a similar schedule to yours, with a springtime launch for the new 540. Things definitely are not going as quickly as I'd like...
I got this far:
...then figured out that I had two problems. The first was that the engine wouldn't turn! It turns out that the Moroso oil pan that's supposed to clear a 4.25 stroke doesn't, at least not in my case. I'll have to modify the internal screen in the pan to clear everything. The second, more significant problem was that the machine shop didn't remove the .030 from the decks that I asked them too, more like .010, so my pistons were still .018 or so in the hole. Low compression, bad quence, no good! Tore everything back apart last night, and dropped the block off at the machine shop about an hour ago... :mad
On a better note, I have the same 335 heads as you waiting for installation, but mine were built with 114 chambers and solid flat tappet springs. Can't wait to get these things running!
Very cool post. I'm planning a 555 short block to replace my 434. The price of race gas is way to high, and I want to drive it more.
All you need now is a shot of spray, and your over 1000 h.p. on pump gas.
Joe
Everything looks great! You have got to be excited about what has been accomplished so far.
This is definitely going to be a killer combination. Your horsepower goals are going to be easily exceeded. Do you plan on putting it on an engine dyno before it goes into the car?
[quote]What size dome did you need to get to 11:1, and what deck height are you running? How do you handle your coolant temp sensor? Intake or heads?[quote]
I'm running SRP pistons w/ a 10cc dome. My deck height is 9.78 and I will run the coolant temp sensor in the intake in the same location as factory intake manifolds.
I'm surprised your Moroso pan did not clear your rods. If nothing else, Moroso has a solid rep for oil pans and oiling systems. Having said that, I have not been terribly impressed w/ aftermarket parts simply "bolting on". Usually some modification is required to fit and work as advertized.
I had a minor problem from my machine shop. I could install the cam, but it was very tight and would not spin. Jim Moore (427Hotrod) suggested I install the cam backwards to help determine where the problem was -- cam or bearing. Same problem installing it backwards, it got real tight at cam bearing no. 2. I called the machine shop and spoke w/ the owner and he simply said "I will be right down and check it out. If it's a problem I will fix it and make it right. I stand behind my work". Rick came down w/ his truck, took some measurements, took the now assembled shortblock back to the shop, fixed the problem and returned the engine to my house. Mistakes happen, but they owned up to it and made it right. I'm sorry to hear your shop did not display the same level of customer service and responsibility.
Can't wait for the springtime launch! We'll have to try and meet somewhere in between. You're in NY right? What part? I'm in southern NH about 1 hr north of Boston.
Hopefully the remainder of your build will be without surprises. Good luck!
Re: 1967 coupe w/548" engine update (69 N.O.X. RATT)
John, hopefully neither Jim or I will scatter transmission parts! If I do, I'll probably take a page from Steve Barker's book and step up to a "real" transmission! Have you made any decisions on your next buildup?
Jim, too bad the race got canceled today. I'm sure you would have got low 10's at mid to high 130's w/ decent air and winding your beast a bit more. When is it rescheduled for? Rita and I have to make it out to see you and Karen next year.
Steve, I hope to engine dyno it, but it will depend on timing and $$$. The machine shop I referenced in my previous post has 2 Superflow dynos and I actually had this engine dyno'd there in its original configuration (Tripower, 9.6:1 CR) back in '92.
How are you making out w/ your 632" monster? How did your "impossible" headers come out? Any pictures???
JoeC427, hood height issues prevent me from running a plate system (I won't run w/o an air cleaner). I suppose a nice fogger system would boost me to over 1000 HP (see Steve 542C2 for a REAL nitrous setup) but honestly I prefer normal aspiration. Any details on your proposed 555?
Thanks for the positive comments. Lets hear more about all your projects!
I just got back from vaca last night and am prepared to start the final assembly on the motor this weekend. The headers are done. Hopefully I can post some pics on Monday or Tuesday.
I'm running SRP pistons w/ a 10cc dome. My deck height is 9.78
I'm running the same 10cc SRP pistons, but my deck height will be a little higher than yours. I asked them to cut .030 off the deck, that would have put me around .008 or so "out of the hole", but they're still trying to talk me out of it. They insist that with a big bore, the piston can rock enough to touch the heads, and that I should keep the pistons at least .010 down in the bore (which would yield a .050+ quench). I'm planning to run a .041 FelPro gasket. I really don't want to take this short block apart again for a long time, so I'm still thinking about calling them back and telling them to take more off the deck.
It sounds like you've got a great machine shop! The shop I'm using seems to do quality work, but I don't think they've seen many of these big bore big block Chevys. Lots of 454, Pontiac, and Hemi parts scattered around the shop.
I'd love to meet somewhere once the cars are back on the road. I'm actually in northern NJ, about 30 minutes from the southern NY border. I'm about 45 miles directly west of NYC. We could take a cruise to Albany, or maybe even to the track at Lime Rock in CT. :) Know of any 1/4 mile tracks in between?
Flareside,
I had the same problem with the Moroso oil pan on my engine (4.25" stroke). I made the holes in the screen larger and then pushed the screen down further. Also had problems with the crank hitting the scrapper.
Corvette Store
1967 coupe w/548" engine update
