Hello Friends! I Just Ordered My New Engine Combo For My 68 Camaro Street/strip Car (driven Daily Half The Year) & Would Love To Hear Some Parts Recomendations From The Experts Here. Its A 434 Sbc With A Dart Block, 4" Eagle Crank & 6" H-beams, Je 11.2-1 F/t Slugs, Pro Topline 235cc Alum Heads W/2.08 X 1.60's & 72cc Chambers, Solid Roller 250 Degrees @ .050, .630 Lift With A 1.5 Rocker, On A 110 Lsa, Super Victor Intake With A 750 Mighty Demon, Msd Dist W/ A 6al. Trans Is A Th350 W/ Approx 3500-3800 Converter (lets See How Long This Trans Lasts). 4.10 Gears, Posi, 12bolt W/ssm Lift Bars & M/t 255/50/15 Drag Radials On Welds. Qa1 Coilover Conversion Up Front & Hotchkis Rear Springs W/kyb's. Car Is A 68, All Steel, Full Interior, No Luxury Options Just The Basics. Probably 3400lbs Ish'? Anyway, Header Selection? I Want To Drop The Gear Ratio (numerically) To Be More Highway Friendly. Any Suggestions On That? Also Any Estimations What My 1/4 Mile E/t Will Be? Any Other Info About Anything Pertaining To The Overall Package Would Be Appreciated! By The Way, You Guys Rock With Your Tech Help In The Past!! Thanks, Bill.

i wouldn't change a thing!
Eric B

No estimates on 1/4 mile times. Just have plenty of clean shorts on hand.

Both pieces might prove a bit too small for "big SB". If heads are done "right" you'll love 'em. With "flat-tops" I believe you'll be in around 10.5:1 C./R. Based on available specs supplied. Assuming 5 cc's for valve notches.Not too big of a deal. It'll probably run on 89 with the alloy heads and a 10.5 number. You don't need to help boost torque with small numbers, these motors produce plenty on their own. Try to keep the heads around 300/310 CFM to keep the torque up some. Thanks, Gary in N.Y.
PS Overall it's a great combo for a 23 degree street-engine! Where were you able to get the heads still? We're still waiting for Comp Cams to release them, through the "RHS" name. I don't know what a 750 "Mighty Demon" is, but you'll need some hefty CFM's on top. My personal opinion only, I don't appreciate the short spring life that comes along with solid rollers when used in conjuction with street-driven cars. They don't lend themselves to stop & go driving and idling. You have to constantly keep your eye on them. We have many of 'em up my way but customers change springs constantly. And all "strokers" don't have turn up high, which makes Hyd-Rollers a better
choice. I have a few units out there from the late '90's still with the same springs. As for gears, you could probably get down to 323/355's with no trade-offs. My son ran a T-350 for 8 yrs. with nitrous and never had a problem in a '66 Chevelle (406 SB) that was at the track every weekend. The T-400's are just too heavy and "eat-up" HP.

thanks gary for the info!! i got the heads from dynaflo performance in vegas. for that matter i got the whole engine there less induction & cam. it should arrive in about 2 weeks. i wanted to maximize power thats why i went solid roller. i'm using comps street mech. rollers with a special oil grove to lube the bearing at idle where solid roller lifters burn up. i'm ok changing springs every year if i have to to reap the benefits of a lightweight solid roller lifter vs a heavy hyd. roller. but i do see your point. in my opinion the solids are worth about 20hp over hyd. you mentioned 300-310cfm on the head flow but at what lift are you refering to? there are a couple of places that still have some pro topline stuff. i went to their website & looked up all their authorized distributors & called most of them. a few places still had some. the mighty demon carb is like the speed demon but w/o the choke horn. it comes milled from the factory like that. dynaflo said that this piston & head combo would be within .1 of a point from being 11.2-1. anyway thanks guys for your thoughts & please keep them coming, bill.

I agree the carb might be a bit small. I also believe the Topline heads have a .300-.400" raised exhaust port which may create clearance problems with most off-the-shelf headers around the pitman arm. Definitely ask around on what headers will work with those heads.

We used the Hedman 1" 3/4's on my dad's '68 with Pro Topline 235's and small block motor mounts with no problems. I have the same headers on my '68 with big block mounts and there are no clearance issues at all.

Look for those CFM numbers around the .650" area. Also, for the pipes, it's probably gonna want 2.000" primarys, but you may have a "fit" problem, the smallest I would accept is 1.875's. We usually test big(ger) SB's with 2.000" on the dyno. Don't forget, your not too concerned with air speed through the intake or out the exhaust with that many inches, that stroke produces some
"serious" torque. Thanks, Gary in N.Y.
PS If the combination works, I would expect somewhere in the neighborhood of 550/580HP. You should likely be nearer to the 565HP mark. I don't have many sheets on this combo, as we usually go the 18 degree route with the +.300 "Rocket" block and a few more inches. It's a tough call, at least for me, with the 23 degree heads. But I'm sure it's gonna move that car.

thanks guys!!! i will get the hooker 2207 1-7/8" super comps. i would rather not use a stahl flange if i dont have to. the adapter plates then may cause clearance issues. i heard some remarks about carb size. what would you all suggest? i have the demon on my current combo & its onlt 6 mos old so i will run it untill funds allow for a bigger carb. i will shift this in the neighborhood of about 6500rpm. any ideas on polishing the chambers? these are not the cnc option heads. flow is down about 20cfm from the cnc chambers. am i going in the right direction by sanding the port walls smooth for less turbulence & polishing the chambers & bowls? not hogging them but just getting a smooth finish & smoothing down the casting marks. thanks, bill.

:D That looks like one stout combo.
A taller tire should help some on RPM for the street (275/60's), but I'm running 3.73's and 27.5" tall tires and at 65ish I'm at 3300rpm, still a little high for me.

If I had to guess, I would say 10.0 - 10.5's. A friend has a simular set up (in a 70 Nova)with a 630 lift SR cam,and 235? Protoplines in a 383,runs 10.8's, and you have a lot more cubes.

Personally, Id build a proper overdrive tranny for it. Yeah, youve got a long 4 inch crank, but your still talking about a motor thats less than 440 cubes with a 250 degree camshaft....its gonna be rad. It will be a torque monster, but I dont expect it to be a low rpm torque monster by any means. Enough to go, but I wouldnt want anything less than a 3.73 gear. Plus, if you go too low on the gearing(numerically low) with the big converter, transmission heat issues will be at a premium cause you will put yourself in a position where your cruise rpm is well under the converters stall speed. With all that mid range torque it oughta produce, that converter will slip a fair amount if you try to gear it to cruise 2500rpm or so with a converter thats capable of probably almost 4000rpm of stall behind that motor. An od tranny with a lockup converter would be the way to go for a motor such as this that is supposed to double as a street car.

Also, if youve already got the lifters, no biggie, but if you ever have a problem with them, Id seriously suggest some isky red zone solid roller lifters or a set of crowers. Those are both very durable lifters in comparison to just about any other. The iskys are nice cause if they do fail, they are completely rebuildable. Finally, dont sweat the carb. A 750 mighty demon is gonna be more of a carb than it sounds like in comparison to your typical carb. If the air fuel metering is right and you arent pulling vacuum at high rpm, than a switch to another carb wont be a dramatic difference if any.......definitely not for the money that a demon carb costs. At the very least, try it out before you consider blowing that kinda money on another carb like that.

thanks greg for the input! i have little faith in o/d trannys. in the past i have had 700r4's break on me constantly with good parts & quality trans techs building them. i would only consider a 4l80e but all in all it would cost me in the $3000 range to swap one in the car. the stand alone computer for it is about $750 alone. i just swapped a 4l80e in my 97 k1500 4x4 (toasted the crappy 4l60e right after i lifted it) & it cost me about $2000+ with free labor from a gm h.d. tech friend of mine. i was able to program the stock ecm with a vin from a truck that had a 5.7 & 4l80e factory. runs great but i lost a ton of power. i installed an art carr 2200rpm 9.5" converter for less rotating weight & a little more stall & it really helped acceleration. by the way, i paid $750 from art carr for this converter & they built it wrong the first time & the second one is out of balance!!! so i think art carr sucks through my experience & be cautious to anyone thinking of buying a converter from them!!! but anyway, back to camaro's, i may have to swap in a smaller converter with the added torque as compared to a 400hp 'ish 350 currently in the car. as for trnnys, i will run the existing th350 until it lets go & then weigh my options. but will probably stick with a 3 speed. my main goal here guys is to spank all the lame import fast & furious wannabees @ the track. up here, weds nights are "run what ya brung" & the track is littered with hondas sporting huge monster tachs & gauges scattered across a "show bar", blasting some sort of rap noise in the lanes & pits. so if i can get an easy 11.50 pass out there i'll be thrilled & spank every one of them!! thanks for the info & i hope i didn't offend anyone, bill.

What valve spring open and seat pressure are they providing with that cam?

I know many others who complain of the 700 trannies as well. It takes a lot to have one last. But, have you considered the 200r4? It may sound like a step down, but they actually have more potential and better gear spacing. Just ask the grand national guys who put those trannies into sub 10 second cars and make em last. A properly built 200 tranny can take some serious abuse. I know of others who are really into them and if you would like, I can dig up some info on who builds a good one or what you need to do in order to really build one right yourself.

i am not sure of the spring pressure. i stated the cam specs & they are building the heads accordingly. i am assuming about 240/650 lbs.

hey greg, i know nothing about the 200r4 trans but i have heard the name thrown around in hi-po conversations. i have blown up 5-700r4's & 1-4l60e. just blow up the sun gear/shell every time. i would be interested in some info on the 200r4. even if i dont go that route, it would be nice to get some education on that trans. about the turbo cars, if i understand them correctly they take a little bit longer to spool up & create great boost as compared to a blower which is more instant or having your converter kick in @ peak torque with a big naturally asp. motor. but i am no expert on anything by any means. i would assume without a big torque hit, drivetrain parts last longer & are not as stressed making a less than indestructable trans live. bill.

Here are a couple of well respected 2004r builders. They ain't cheap, but you get what you pay for.

http://www.ptsnctb.com/

http://www.ckperformance.com/

Jody the Mod. here can tell you where to get a 200-4R there in Cali. because he has one behind his Blown 540 that makes around 1000hp, and the 200-4R holds up. If you spend the $$$ and get them built they can take 900+hp from what I hear. My 200-4R has been in my truck for over a year, and I drive it a lot, and still holdin up fine, but it dont make no power...
If youre gonna do some port work on the heads, do the bowl work and nock down the guides, and polish the cchambers, while unshrouding the intake valves. You can polish the intake and exhaust ports too since theyre going on a big motor. If you wanna see some before after pics of home ported heads, and whats been done check out the bottom of my webpage.
I'd recommend an HP950 Holley for it, its a 750 body / 850 baseplate, works really well on the street. (even on my mild 383)