I would say likely a function of the port job on the heads and intake. I don't remember Greg's levels of porting and how he described them(I only recall seeing his website once before it came down) but this was a Level 3 effort.
Were your Gessler heads the "wild" ported ones pictured on his site with the inside bowl valve guides machined completely off? And they were filled runners. Those looked like his best effort port work.
An important number for comparison is what does a stock 350 SP Buick 350 make on the same dyno under the same conditions? I suspect 250-300 hp max. What do you say?
Because its a small block. It doesn't matter in this case because the torque is 378.7 @ the same RPM, torque gets you moving and HP takes you across the finish line. Having 378.7 ft lbs of torque is plenty to get his car moving, look at how flat torque curve is! Plenty of torque to fry the tires at will with a 3 series gear! The less cubes, the more you have to spin it to make power. The nascar 358 cid engines that make 850 + HP have to spin to 9,000 + to make that kind of power. That's why the N/A QM small block engines need more gear and stall to get off the line, to get into the power range. The reason I like a stroker small block, the extra cubes pulls the power range down a bit to make more power in a useable RPM range. With a sbb and a dual plane intake, you can see by the above example that it makes plenty of low end torque. I would guess with an extra just 20 cubes in the above engine that there would be around 50 to 75 more ft lbs and 20 to 50 more HP?!
Mart, Yes, the exhaust guide was removed completely from the port on these heads. Intakes had pushrod holes tubed, but he did not break thru to the tubes. Moderate bowl work, just polished chamber. A mid level port job... JW
It has more power on both than mine, it will go 12's with a 373 and a 3000 stall. I went 13.31 with a suspension that absolutely will not move. 400 ft lbs from 4000 rpm to 5000 rpm it will roll. Put that 3500 stall convertor in there footbrake it to 3 grand and it is going to launch like a... It is going to rock. I would stick a 200 -4 trans in there 3000 stall with lockup and with a 410 gear, you will kick but on the street and track. The rpm's will be low too. It will be a sleeper keep the exhaust quiet. I guarantee this will be the one to beat. Time to step up to the plate boys. Talkin is over.
Must have been straightening the int. runners some. Wonder who has those "wild" max port heads? They looked slick...
I don’t remember the name of the fellow who greg made those wild heads for but I talked with him on the phone once... he had a stroker setup, hogan custom intake and about 12.5:1 compression. He had some serious $ into it and I remember it was about 600 Hp NA. He was spinning to about 7500 rpm I remember. This was in 2005. I also talked with greg gessler about the heads and he stated the guys name as well. He had a bad divorce and I lost track of him as he changed his number. I have a brief write up about the combo in my book, but I don’t have my computer in front of me.
Curious myself. '70 SP, bone stock. I have one in my car, but it's got a crower lvl3. Man I wish there were engine dynos in Iowa.
Factory assembled '70 SP was dyno'ed @ 385 ft. lbs. @3100 RPM and 270 hp @4650 RPM. (actual real world dyno, not a sim) More could be achieved with 'blueprinting', no doubt. Torque seems to be similar, but hp shoots way up when you open up the air flow. Very nice results on the build here, particularly when using the factory exhaust manifolds and all that extra head work and roller cam trying to push through them. Thanks for posting these long-awaited results and all the hard work involved.
It would be interesting to see that factory 350 make 385 ft lbs, stock.. the factory 455 was rated at 510, but I have seen them make 460ish numbers several times, even when warmed over a little bit. 1970 "SF" 455 w/ light head porting,manifolds a 212 cam.. makes the factory claim in HP, but not close on torque. No idea if the 350 would be the same, but I would not be surprised. JW
Agree, stock #'s are BS, I would be surprised to see a stock 350 make 385 as well, no way the 315hp made its claimed 410ftlbs
Stock #s (advertised) on the '70 SP were in fact BS, as were most of the factory ratings on pretty much every manufacturer. The numbers I posted came from an article where a GS 350 was dyno'ed, along with others (350 and 327 chevy), which didn't make anywhere near the advertised numbers. Two dyno pulls were made, and the 385@3100 and 270@4650 were the resulting average for the Buick 350. Still, a far cry from 410 and 315.
By virtue of comparison, a GM engineering document on the Buick 430 back in 1967 showed the 430 having an actual (averaged) static compression ratio of 9.4:1 (not 10.25:1), yet still managed to produce 452.8 ft. lbs. @3200 RPM and 344.3 hp @5000 RPM, despite the 'advertised' ratings of 475 ft. lbs. and 360 hp @ the same RPMs. That's only 22.2 ft. lbs. and 15.7 hp less than advertised, and with much less than advertised compression ratio. Seems the 430 was a pretty darned good engine. (I've posted this elsewhere on this forum in the past) This was an engine they grabbed off the assembly line. Factory ratings were less than advertised, sure, but according to what I've seen losses of 50+ ft. lbs. only comes from using aftermarket camshafts that weren't engineered by the Buick team. Some do better than others, as is to be expected, and variances will always be observed from engine to engine and dyno to dyno, no matter which parts are used. Back to the '70 SP Buick 350, the advertised 410 ft. lbs. was 25 ft. lbs. too generous, and a whopping 45 hp over the actual mark. Still a strong runner for its day, but it just goes to show how numbers sell amidst a highly competitive market. The Buick 455 was also a victim of this. Torque figures for a factory Stage 1 455 were more like 480ish ft. lbs., which was still a big jump from the 450-460 ft. lbs. the 430 and non stage 455s saw. People get too obsessed with numbers, so when they see actual power output less than advertised numbers, they may think something went wrong. It is what it is, the engines are still strong, no matter what the computers say. To see real 400 hp numbers is very impressive for a mild Buick 350 using iron heads. Good job, I say.
See this boys this is what you will get with the 212 cam runs good great TQ and put in a 2004r trans with a 373-410 gear lockup the TQ convertor and I think you can get into the mid 13's easily with that set up Now you add those alum heads and you just might get 375hp and 420TQ. makes a nice street runner with not a big cam This motor was built before 2010 so what you all waiting for next year? ooops guess so lol
I agree, plus they get duped into believing them. Kinda related, I was shopping for a new air compressor, the specs are important as far as a certain CFM at a certain PSI for running air tools, the generic makes must use a different rating, 'cause I see single stage pumps and small tanks out doing the name brand ( IR, Campbell Hausfeld, Quincy, etc.) with two stage pumps and bigger tanks. Its all in where the ratings are taken. I recently blew up a Fortress (Harbor Freight) compressor cause I over worked it, BUT, it said 200 psi max pressure and 5.7 CFM at 90 PSI, told my boss I'll blow that thing up from over working it, he said " Its ok, its just temporary" People get all warm and fuzzy with big numbers, it all depends on how those big numbers actually work, if they do actually work
Isn't that where SCFM comes into play? IIRC the "S" stands for Standard and standardized the testing for exactly the reason you stated.
