Heads and cam
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,809
From: Cool Northern Michigan
I do have an Air Gap and live in one of the coldest regions of the nation. (49* this morning)
For what its worth, that Intake is a "street" unit, not just racing.
Never heard of a Intake freezing up. Sounds more like some carb issues, blaming the Intake maybe.
For what its worth, that Intake is a "street" unit, not just racing.
Never heard of a Intake freezing up. Sounds more like some carb issues, blaming the Intake maybe.
Last edited by HeadsU.P.; Jul 8, 2021 at 08:24 PM.
Pro
Joined: Apr 2015
Posts: 551
Likes: 142
From: Warrington PA
For what its worth putting heads on an other wise "un-know" base (short block) is like putting perfume on a pig, you dont know how long it will last with any of the said "ad on's" ? if you want power then buy or have your engine rebuilt for the power you desire. and dont forget to address the trans of choice you may have, to properly apply that new power to the ground. Just my $0.02
Race Director
Joined: Nov 2006
Posts: 13,065
Likes: 7,678
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
For what its worth putting heads on an other wise "un-know" base (short block) is like putting perfume on a pig, you dont know how long it will last with any of the said "ad on's" ? if you want power then buy or have your engine rebuilt for the power you desire. and dont forget to address the trans of choice you may have, to properly apply that new power to the ground. Just my $0.02
And then the Story just begins. More horse power means more heat. bigger radiator, better fan or fans. more electricity to run electric fans. then everything behind the engine. trans? manual or auto? new torque converter? heavily modified trans to hold the power? U joints? Drive shafts and half shafts? Rear diff??? and this just scratches the surface. I've been tinkering on mine for many years.
Yes I can light em up all the way down the street. And yes, I keep finding the weakest link.
Last edited by 4-vettes; Jul 9, 2021 at 06:29 AM.
Drifting
Joined: Aug 2019
Posts: 1,506
Likes: 495
First off he knows he has flat top pistons . second installing good heads is not putting perfume on a pig .... Installing good heads on a block that's already knocking is putting perfume on a pig . there is no secret sauce on a SBC as the info is out there and been out there for years ..
I arrived at my 400 HP based on Comp cams own test of a XE262 , 348 horse power with 9.5 to 1 350 bored .040 and Dart SR (stock replacement ) cylinder heads , add Promaxx 183ccintake port that flows 250 cfm at .500 lift with 64cc chamber for 10.? and that's my recipe for 400 hp .... Hot Rod got 440 hp with the same test and AFR 195's (edit to add ) so I compute 400 easy based on that .... Yes I own a Moroso speed calculator for over 35 years and it comes out a 300 horse power RWHP but there's not a bone stock 300 hp or 350 hp Vette made that could run with my Vette as it sits right now
COMP Cams XE262H Dyno Results
I arrived at my 400 HP based on Comp cams own test of a XE262 , 348 horse power with 9.5 to 1 350 bored .040 and Dart SR (stock replacement ) cylinder heads , add Promaxx 183ccintake port that flows 250 cfm at .500 lift with 64cc chamber for 10.? and that's my recipe for 400 hp .... Hot Rod got 440 hp with the same test and AFR 195's (edit to add ) so I compute 400 easy based on that .... Yes I own a Moroso speed calculator for over 35 years and it comes out a 300 horse power RWHP but there's not a bone stock 300 hp or 350 hp Vette made that could run with my Vette as it sits right now
COMP Cams XE262H Dyno Results
Last edited by Eric P; Jul 9, 2021 at 09:37 AM.
Le Mans Master
Joined: Apr 2011
Posts: 6,284
Likes: 1,170
From: Hermosa
First off he knows he has flat top pistons . second installing good heads is not putting perfume on a pig .... Installing good heads on a block that's already knocking is putting perfume on a pig . there is no secret sauce on a SBC as the info is out there and been out there for years ..
I arrived at my 400 HP based on Comp cams own test of a XE262 , 348 horse power with 9.5 to 1 350 bored .040 and Dart SR (stock replacement ) cylinder heads , add Promaxx 183ccintake port that flows 250 cfm at .500 lift with 64cc chamber for 10.? and that's my recipe for 400 hp .... Hot Rod got 440 hp with the same test and AFR 195's (edit to add ) so I compute 400 easy based on that .... Yes I own a Moroso speed calculator for over 35 years and it comes out a 300 horse power RWHP but there's not a bone stock 300 hp or 350 hp Vette made that could run with my Vette as it sits right now
COMP Cams XE262H Dyno Results
I arrived at my 400 HP based on Comp cams own test of a XE262 , 348 horse power with 9.5 to 1 350 bored .040 and Dart SR (stock replacement ) cylinder heads , add Promaxx 183ccintake port that flows 250 cfm at .500 lift with 64cc chamber for 10.? and that's my recipe for 400 hp .... Hot Rod got 440 hp with the same test and AFR 195's (edit to add ) so I compute 400 easy based on that .... Yes I own a Moroso speed calculator for over 35 years and it comes out a 300 horse power RWHP but there's not a bone stock 300 hp or 350 hp Vette made that could run with my Vette as it sits right now
COMP Cams XE262H Dyno Results
I suppose it's in the realm of possibility to get 400 HP out of a xe262 with the right heads, right exhaust and good tuning. If you look at the XE 268 it does no better than the XE 262 on Comp's dyno results. I suspect if you were to up the CR to 10:1 instead of 9.25:1 you'd see the 268 shine with the same heads. give it good heads and a 10:1 and you'd make much more peak power and better bottom end power without exceeding max dynamic CR. The XE 262 you're gonna have to keep an eye on the dynamic CR in order to not exceed pump fuel limits.
The performance of those two cams is so similar that the dyno's could almost be laid over each other with the set up they gave the cam to work with.
More duration needs more CR to work well.
I'm not a fan of the flat tappet XE series myself and would rather do it with a roller cam of similar specs. There are just too many guys who end up with flat lobes on that series for my comfort zone.
Last edited by REELAV8R; Jul 9, 2021 at 10:54 AM.
Drifting
Joined: Aug 2019
Posts: 1,506
Likes: 495
Hot Rod also noted less power with XE268 with AFR 195 also , I hear you on the flat tappet as my shop will never install another one , roller or nothing ( I run Schubeck's flat tappets in my Ford FE and the camshafts look brand new when you take it out even after years of use ). Ken Ellison has a new part two video on the recent lifter failure rate ...... OP stated in the middle of the thread he has flat tops
