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AFR vs Vortec vs ?
- Thread starter Greg Ducato
- Start date
I know it's not exactly the same thing, but a co-worker installed a GM Vortec long block 350 in his '92 pickup. From my understanding the main difference between the original TBI engine and Vortec long block was the heads. He just removed the stock long block and bolted in the new using the same TBI and did no tuning or anything. It had a pretty significant increase in power with zero mods or adjustments to the TBI system. And before somebody asks, the original engine appeared to be in good shape and not real high mileage so the comparison is not with a ragged out, poor running engine. This is a whole other story, but the reason for the new engine is that the guy's wife took the truck to work since it was snowing and managed to shift it into 4 low. Once on the highway the road was clear so she tried to go the speed limit, again in 4 low. She basically made a 60+ mile round trip with the throttle pegged to the floor and the engine didn't like it too much.
Thanks, any idea what intake manifold was used and what was done about egr?
How many miles are on the engine and do you know what your compression looks like? Reason I ask is that I've seen more than one occasion where someone slaps a fresh top end on a motor or reuses old heads on a shortblock, and the result is that the strong new part exposes or exacerbates weaknesses in the existing part.
If you plan on keeping the TBI and using Vortec heads, you may just want to get a chip with an EGR delete, if you don't require emissions inspection.
If you plan on keeping the TBI and using Vortec heads, you may just want to get a chip with an EGR delete, if you don't require emissions inspection.
He used the GMPP Vortec to TBI intake and left the EGR disconnected. If I remember correctly it would sporadically throw an EGR code but did not seem to effect performance any. I'm sure with a custom tune he could have made it run even better.
Engine has 62,000 original miles, doesn't leak a drop of oil, has very good compression. I plan to upgrade to a 383 sometime down the road so the mods I make to this engine will ideally be applied to the next one. I have wrestled with the EGR dilemma and I would like to retain it for best mpg and cooler intake charge at the throttle positions the engine normally operates at.
Thanks, I have purchased the Vortec EGR tube and valve some time ago in case I go went this route, I had planned to weld a bung into a header tube to make that system work if I ended up going Vortec.
I have an 89 blazer with a built 350 running AFR 180cc heads and i'm VERY happy with the performance. I am also running a 454 TBI unit though and have a "tune" done.
AFR is FAR superior to any other aluminum head out there today. Yes back in the day before AFR was around Brodix and Canfield were the heads of choice but AFR has nailed it with their 100% CNC porting and air flow hands down.
AFR is FAR superior to any other aluminum head out there today. Yes back in the day before AFR was around Brodix and Canfield were the heads of choice but AFR has nailed it with their 100% CNC porting and air flow hands down.
Thank you for sharing that info, I was hoping you might weigh on on this. What intake are you using? Headers? Are you using the 464 injectors as well? What cam are you running? Sorry for all the questions, I have observed that you are detail oriented and was hoping you could share your opinion and recipe.
350 block bored .030" oversize with torque plates, squared and zero decked
Stock 3.48" stroke
KB193 piston (12cc dish)
Scat I beam 5.7" rods
AFR 180cc angle plug heads
Comp Cam roller cam (8-464-8) .550"/.546" lift, 202*/212* duration @ .050" on 113* lobe seperation installed at 109* intake centerline
Cloyes timing set (9-3145A)
Comp Pro Magnum full roller rockers (1305-16)
Comp push rods (7608-16)
Stock intake that was taper bored for the 454 TBI unit running the stock 5235231 injectors that were flow tested at 96.5 lbs/hr @ 18 PSI
Flowtech shorty headers (91830)
Compressioon ratio works out to 9.489:1
Stock 3.48" stroke
KB193 piston (12cc dish)
Scat I beam 5.7" rods
AFR 180cc angle plug heads
Comp Cam roller cam (8-464-8) .550"/.546" lift, 202*/212* duration @ .050" on 113* lobe seperation installed at 109* intake centerline
Cloyes timing set (9-3145A)
Comp Pro Magnum full roller rockers (1305-16)
Comp push rods (7608-16)
Stock intake that was taper bored for the 454 TBI unit running the stock 5235231 injectors that were flow tested at 96.5 lbs/hr @ 18 PSI
Flowtech shorty headers (91830)
Compressioon ratio works out to 9.489:1
Nice!!' Thank you, that is more cam than I thought could be run with TBI , computer mods?
I had Brian at TBIchips burn a chip for me based on that info alone.
Cool, thanks!
So you are saying that since your 454 TBI equipped "built" 355 with 202 degrees of intake duration runs good, AFR is the best out there?
AFR is an excellent head yes, good quality, excellent machining, and made in USA. I never said they were bad. But saying they are the best out there is a pretty biased opinion that isn't really based on facts. If you go to the race track and see what makes the most power and runs the fastest, it isn't AFR. And they aren't the only head company with CNC porting. Many people aren't looking for the most power though, and AFR is a good head, no doubt about it.
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Those specs are with 1.6 ratio rockers. With std rockers the lift would be .518/.513. Still a very nice cam for that TBI engine with those specs and that wide LSA. The use of 1.6 ratio rockers with the TBI and those heads probably works well to increase lift while keeping the overlap down and the computer happy. Hydraulic roller cams are the way to go.
My cam specs with stock rockers are 202/207 0.450/0.460 lift 116 LSA
I don't want to stir anything up really, but when looking at heads for a truck, and not some racing application, the execution of the finer details is probably a LOT less important than the major details like screw in vs. press in studs and chamber design. Port flow matters, but realistically, if you get an extra 5-10HP out of a really well done port, you aren't going to notice. (my point is, if you can afford/justify it to yourself, get the best there is...if cost is a consideration, I don't feel you are giving much up not spending as much but still going with proven heads)
I haven't even compared prices of the various heads. IMO the Vortecs lack because they are iron (I'm a weight weeny, so sue me) they come with weak springs as installed, require special intakes, and they have press in studs. Once you correct the perceived/actual weaknesses as necessary, price starts to approach aftermarket AL heads with better components.
FWIW, with new fuel pump...really the tank hose was the issue...and driving around this past weekend a bunch, I was reminded how much fun the TPI setup is when running right. 55MPH (at ~3300RPM) and there is still plenty of power left to keep going. Passing is kind of fun now.
Based on best-case specs for the L05 and L98 in stock trim (as best I can deceipher) the TPI was worth 35HP and 35ft lbs, the L31 netted 100 more HP than even the best TPI, so I would think with a mild cam and fast burn chamber, TPI with +50 hp/ft lbs over the L05 is going to be pretty easy.
Going TPI over upgrading TBI is likely to be fairly time consuming and a bit expensive (new injectors, plumbing intake tract, re-wiring, new fuel pump, new fuel lines up front at least) but I don't regret choosing TPI over TBI at all. I regret going gas over diesel, but that's another argument entirely.
TPI
I haven't even compared prices of the various heads. IMO the Vortecs lack because they are iron (I'm a weight weeny, so sue me) they come with weak springs as installed, require special intakes, and they have press in studs. Once you correct the perceived/actual weaknesses as necessary, price starts to approach aftermarket AL heads with better components.
FWIW, with new fuel pump...really the tank hose was the issue...and driving around this past weekend a bunch, I was reminded how much fun the TPI setup is when running right. 55MPH (at ~3300RPM) and there is still plenty of power left to keep going. Passing is kind of fun now.
Based on best-case specs for the L05 and L98 in stock trim (as best I can deceipher) the TPI was worth 35HP and 35ft lbs, the L31 netted 100 more HP than even the best TPI, so I would think with a mild cam and fast burn chamber, TPI with +50 hp/ft lbs over the L05 is going to be pretty easy.
Going TPI over upgrading TBI is likely to be fairly time consuming and a bit expensive (new injectors, plumbing intake tract, re-wiring, new fuel pump, new fuel lines up front at least) but I don't regret choosing TPI over TBI at all. I regret going gas over diesel, but that's another argument entirely.
TPI
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That's very mild duration and lift, his cam is almost identical duration with more lift for more power without changing the RPM range really.
I agree, and that is why I was saying I wouldn't spend a bunch of money on heads for a TBI engine, because mediocre heads won't be the bottleneck with the limitations on the camshaft and fuel injectors. Without the TBI, heads and cam are much more open and there is a lot more potential. But then you open up a whole new can of expensive worms, and maybe he doesn't need that performance here?
In my research for when I built my 355, I found the AFRs to be the top of the food chain as far as power and quality. I ended up going with Patriot Performance which despite the name is a foreign head. I went with them for the bang for buck aspect. A few thousand miles later they warped and the inner dampener springs broke. The machine work and valve work required to fix them was more than I paid for them. I replaced them with a set of Darts and haven't looked back. (The Darts where still cheaper than the AFRs but very similar in flow numbers.)
Thanks for all the comments and opinions guys, just what I was looking for. If anyone has a similar build or engine please fell free to comment. The top end I use on this engine will probably be applied to a 383 down the road so that does factor into my choices.
