[Jandro]

The following is the exact description I had when I purchased the engine:

73 455 + .030,stock resized rods with arp bolts,sfi approved and degreed harmonic balancer,srp forged pistons with moly rings,6X8 heads by Ken Keefer(PDude),milled to 92 cc's,p/p,intake ports raised to RAIV,Flow's 240 intake/200 exhaust at .500 lift at 28".Comp's 995 springs with BBC 7/16 studs,2.11/1.77 ferrea s/s valves.Comp magnum 1.5 roller tips with poly-locks.Bronze guides and push rod holes elongated for 1.65 rockers.Comp XR288HR hyd roller cam,236/242 @ .050 .520/.540 lift with the 1.5's.Elderbrock timing chain(cam installed straightup).RPM with 1" spacer and stock holley 850dp with air horn milled off.

Something that concerns me is that I have Comp cams XE288HR and I have noticed that the LSA is 110, so this should effectively raise the required octance versus the same engine with a different cam with a wider LSA. So, can this engine safely run 93? I purchased the engine built this way, by the way.

So what's the compression ratio based on this info?

THANKS FOR LOOKING!

[Jandro]

The following is the exact description I had when I purchased the engine:

73 455 + .030,stock resized rods with arp bolts,sfi approved and degreed harmonic balancer,srp forged pistons with moly rings,6X8 heads by Ken Keefer(PDude),milled to 92 cc's,p/p,intake ports raised to RAIV,Flow's 240 intake/200 exhaust at .500 lift at 28".Comp's 995 springs with BBC 7/16 studs,2.11/1.77 ferrea s/s valves.Comp magnum 1.5 roller tips with poly-locks.Bronze guides and push rod holes elongated for 1.65 rockers.Comp XR288HR hyd roller cam,236/242 @ .050 .520/.540 lift with the 1.5's.Elderbrock timing chain(cam installed straightup).RPM with 1" spacer and stock holley 850dp with air horn milled off.

Something that concerns me is that I have Comp cams XE288HR and I have noticed that the LSA is 110, so this should effectively raise the required octance versus the same engine with a different cam with a wider LSA. So, can this engine safely run 93? I purchased the engine built this way, by the way.

So what's the compression ratio based on this info?

THANKS FOR LOOKING!

[Doug Christie]

CR, assuming 0 deck, 6cc valve reliefs, and .040 squish it should be about 9.8:1.

[Jandro]

It hasn't been zero decked (if i remember correctly). And the valve reliefs... hmm... not sure.

The only info PDUDE has on his site that seem to be the same "treatment" my heads had is the following: "I use the 6X-8 400 Pontiac heads, ported to 245 cfm on the intake side. Raise roof to Ram Air IV specs, elongate pushrod holes, install 7/16" adjustable rocker studs, resurfaced on three sides. Install 2.11 Intake w/oversize 1.77 Ferrea Stainless Steel Valves.
"

9.8 Comp and a Hydraulic Roller cam with a LSA of 110 too much for 93 you think?

Thanks Doug, and anyone else chiming in.

[DiamondJim]

Using : Bore 4.18, Chambers 92cc, Valve releifs 5cc(SRP's), Area above top ring 1cc, Compressed gasket .041, Deck clearance .005, Static compression is 9.73. Using an intake closing point(XR288R) of 44 degrees ABDC, DCR is 8.84. Refuse to make any call on Octane required, I defer to the Dude. Heck, If he told me it would run on it, I would Pee in my gas tank- He's Da Man- JimT

[Jandro]

Hey you're in GA! I should probably change my "location" I'm from Atlanta and live in Macon now (going to graduate school in the spring). Maybe I'll see ya around!

I guess I'll have to get Pdudes attention. He didn't build the motor, someone else did. It is just his heads. Thanks!

[Rholmes]

Jandro with the help of Pdude and Comp's tech that combination was well thought out.Pistons are 6cc valve relief and are .01 in the hole.I wonder what had happened to you since I hadn't heard back from ya.Haven't you fired that engine up yet?You will be fine with 93 octane fuel.The last engine I built had a 248 TFX solid with # 46 heads(74 vintage) that do not flow as well as Ken's(6X's)at low lift.And they propeled a stock bodied 74 GTO to 7.80's 1/8 mile with 170's 60 ft.What carb did you decide on?If you're not going to use the 850dp,contact me.You should easily beat your friend's 12.80's 1/4 time with the 355's/373's we discuss.Keep the initial timing 10-12 and total @ 34 @ 2800-3000 rpms and tune from there.If using MSD's ignition(HINT!,HINT!),use one light silver spring and one medium blue spring in the distributor.Shift points 5600-5800,or bring it to me for the complete break-in

[Jandro]

OH yeah, we fired it up alright. It fine I was just having timing issues, we put in the wrong springs (oops!). Springs have been switched out BUT apparently the timing keeps dropping off still? Should I just lock the timing out? I would bring it to ya Roger but I moved to Macon, GA! Go figure huh? Thanks!

[Bulldog]

Jandro, I think youll be fine running 93 maybe even 92 octane. I run a 455 w/4X-7H heads (2.11/1.77 valves)and 9.4 to 1 compression, 1.65 rockers, Crane Power Max Hydraulic Cam H-288-2 (.503/.520) which has a 114 LSA, Flat Top pistons, Edelbrock Performer RPM intake, Rochester Quad (rebuilt-800cfm) and I use 89 octane but I used 92 when I did the break in runs.

[Jandro]

Hey thanks! I appreciate it!

[Rholmes]

Jandro,if you haven't already,order Jim Hands book,on page 122 CVM outlines the engine that you have,with the excepting of me increasing the c/r for the slightly larger cam.You mentioned "timing dropping off".Can you be more specific?What ignition system are you using?MSD's are the tried and true at ALL level of high performance.I really would like to see your 1/8 &/or 1/4 mile times with 60 ft and mph,later,Roger

[Jandro]

Hey Roger, car just dynoed at 335 HP @ 4600 to the wheels on a SUPERFLOW DYNO and 380 FT/lbs @ 4500... I'll give better estimates in a little bit.

Jandro

PS FROM my research superflow dynos "low" compared to other dynos (i.e. dynojet)... that's good to know

[denpsim]

I have virtually the same set up, runs great on 93 octane. I live in Wichita Falls Texas and the summers here are killer. My heads are 6x 4s ported with 2.11 1.77 valves. I think you will love this combo. Use the BOP dist gear.

[nosliw]

dont think its necessary to make a new thread so here goes...

ive got a 67 tempest with what i think to be a 66 326. the code on the upper passenger side of the timing chain cover is "YN"

the guy i bought it from said it was a 389. but i checked it out in my chiltons and it's a 326

can you tell me as many specs as you can on it? i cant seem to find the info anywhere...

oh, it's got a 260cfm holley on it from an '86 chevette... bought it that way, just cant afford a new carb yet

[Jandro]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by denpsim:
I have virtually the same set up, runs great on 93 octane. I live in Wichita Falls Texas and the summers here are killer. My heads are 6x 4s ported with 2.11 1.77 valves. I think you will love this combo. Use the BOP dist gear. <HR></BLOCKQUOTE>

Hey thanks, did you ever dyno it? What does it run in the quarter and in what car?

[Rholmes]

Jandro that combination should continue to make hp above 4600rpm(@ least to 56-5800).What carb are you using?Should be @ least 830 cfm with 1" spacer(hood clearance allowing).What ignition system?Make sure you're @ least 30-34 total timing between 2800-3000 rpm's.I personally prefer holley carbs(something I'm more familiar with) and MSD'S ignitions with pro-billet distributor (I don't concern myself with vaccum advance for gas mileage).Seek out and join a local Pontiac club in your area.I have chatted with a Tim Simpson(goatseeker) who resides in Ga.,maybe he can steer you in the right direction for membership.DO NOT depend on anyone not familiar with Pontiac engines wrenching (my)oops! your new engine
I'm trying to build my 69 WS Judge 400 to make equilvalent power using the RA exhaust without "stroking" the engine

[johnta1]

wilson,go here and input your YN in the engine codebox.